WAEC SSCE - General Mathematics - 2019

If 23\(_y\) = 1111\(_{\text{two}}\), find the value of y

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Evaluate: 2\(\sqrt{28} - 3\sqrt{50} + \sqrt{72}\)  

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To evaluate the expression 2\(\sqrt{28} - 3\sqrt{50} + \sqrt{72}\), we need to simplify the square roots first. \(\sqrt{28} = 2\sqrt{7}\) \(\sqrt{50} = 5\sqrt{2}\) \(\sqrt{72} = 2\sqrt{18} = 2\sqrt{9}\sqrt{2} = 6\sqrt{2}\) Now that we have simplified the square roots, we can substitute the values back into the expression: 2\(\sqrt{28} - 3\sqrt{50} + \sqrt{72}\) = 2 * 2\(\sqrt{7}\) - 3 * 5\(\sqrt{2}\) + 6\(\sqrt{2}\) = 4\(\sqrt{7}\) - 3 * 5\(\sqrt{2}\) + 6\(\sqrt{2}\) = 4\(\sqrt{7}\) - 15\(\sqrt{2}\) + 6\(\sqrt{2}\) = 4\(\sqrt{7}\) - 9\(\sqrt{2}\) So the expression evaluates to 4\(\sqrt{7}\) - 9\(\sqrt{2}\).

The total surface area of a solid cylinder 165cm\(^2\). Of the base diameter is 7cm, calculate its height. [Take \(\pi = \frac{22}{7}\)]

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Evaluate: (0.064) - \(\frac{1}{3}\) 

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Factorize completely; (2x + 2y)(x - y) + (2x - 2y)(x + y) 

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To factorize the given expression, we can use the distributive property of multiplication over addition. This means that we need to multiply each term in the first set of parentheses by each term in the second set of parentheses, and then simplify: (2x + 2y)(x - y) + (2x - 2y)(x + y) = 2x(x - y) + 2y(x - y) + 2x(x + y) - 2y(x + y) (using distributive property) = 2x^2 - 2xy + 2xy + 2y^2 + 2x^2 + 2xy - 2xy - 2y^2 (combining like terms) = 4x^2 - 4y^2 Therefore, the answer is 4(x - y)(x + y). Explanation: We can factorize the given expression by grouping the terms into two sets, each set containing two terms with a common factor. We can then factor out that common factor from each set, and simplify. In this case, we can factor out 2 from the first set of parentheses, and -2 from the second set of parentheses, giving us: 2(x + y)(x - y) - 2(x + y)(x - y) We can then combine the two sets of parentheses, giving us: (2(x + y) - 2(x - y))(x - y) Simplifying the expression inside the parentheses gives us: (2x + 2y - 2x + 2y)(x - y) Which further simplifies to: 4y(x - y) However, this is not the fully factored form, since we can factor out 4 from the expression to get: 4(x - y)(y) So the answer is 4(x - y)(y), which is equivalent to option A.

In the diagram, PQ is parallel to RS, < QFG = 105\(^o\) and < FEG = 50\(^o\). Find the value of n

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If 3p = 4q and 9p = 8q - 12, find the value of pq.

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Evaluate; \(\frac{\log_3 9 - \log_2 8}{\log_3 9}\) 

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We can use the laws of logarithms to simplify the expression: \(\frac{\log_3 9 - \log_2 8}{\log_3 9} = \frac{\log_3 (3^2) - \log_2 (2^3)}{\log_3 (3^2)}\) Using the laws of logarithms, we can simplify the numerator: \(\frac{\log_3 (3^2) - \log_2 (2^3)}{\log_3 (3^2)} = \frac{2\log_3 3 - 3\log_2 2}{2\log_3 3}\) We know that \(\log_3 3 = 1\) and \(\log_2 2 = 1\), so we can substitute these values: \(\frac{2\log_3 3 - 3\log_2 2}{2\log_3 3} = \frac{2 - 3}{2} = -\frac{1}{2}\) Therefore, the value of the expression is -\(\frac{1}{2}\).

Express, correct to three significant figures, 0.003597. 

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To express 0.003597 correct to three significant figures, we need to round off the number to the third digit after the decimal point. The third digit after the decimal point is 7. Since 7 is greater than or equal to 5, we need to round up the second digit after the decimal point. Therefore, the third digit becomes zero. Hence, the rounded value of 0.003597 correct to three significant figures is 0.00360. Therefore, the answer is: 0.00360.

If tan x = \(\frac{3}{4}\), 0 < x < 90\(^o\), evaluate \(\frac{\cos x}{2 sin x}\) 

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We are given that \(\tan x = \frac{3}{4}\) and \(0 < x < 90^o\). Since \(\tan x = \frac{\sin x}{\cos x}\), we can rewrite the given equation as: \[\frac{\sin x}{\cos x} = \frac{3}{4}\] Multiplying both sides by \(\cos x\) gives us: \[\sin x = \frac{3}{4}\cos x\] Dividing both sides by \(2\sin x\) gives us: \[\frac{\cos x}{2\sin x} = \frac{\frac{4}{3}\sin x}{2\sin x} = \frac{4}{3} \cdot \frac{1}{2} = \frac{2}{3}\] Therefore, the value of \(\frac{\cos x}{2\sin x}\) is \(\frac{2}{3}\). Hence, the answer is: \(\frac{2}{3}\).

Find the angle at which an arc of length 22 cm subtends at the centre of a circle of radius 15cm.  [Take \(\pi = \frac{22}{7}\)]

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In the diagram, POS and ROT re straight lines. OPOR is a parallelogram, |OS| = |OT| and

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Solve 4x^{2}\) - 16x + 15 = 0.

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In XYZ, |YZ| = 32cm, < YXZ 53\(^o\) and XZY = 90\(^o\). Find, correct to the nearest centimetre, |XZ|

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An arc subtends an angle of 72\(^o\) at the centre of a circle. Find the length of the arc if the radius of the circle is 3.5 cm. [Take \(\pi = \frac{22}{7}\)]

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To find the length of the arc, we need to use the formula: Length of arc = \(\frac{\text{angle subtended by the arc}}{360^\circ} \times 2\pi r\) Here, the angle subtended by the arc is 72\(^o\) and the radius of the circle is 3.5 cm. We can substitute these values in the formula to get: Length of arc = \(\frac{72^\circ}{360^\circ} \times 2 \times \frac{22}{7} \times 3.5\) cm Simplifying this expression, we get: Length of arc = \(\frac{1}{5} \times \frac{44}{7} \times 3.5\) cm Length of arc = \(\frac{22}{5}\) cm Length of arc = 4.4 cm (approx.) Therefore, the length of the arc is 4.4 cm (option C).

Eric sold his house through an agent who charged 8% commission on the selling price. If Eric received $117,760.00 after the sale, what was the selling price of the house? 

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The commission charged by the agent is 8% of the selling price. This means that the remaining amount that Eric received after the sale is 92% of the selling price (100% - 8% = 92%). We can set up an equation to solve for the selling price: 92% of selling price = $117,760.00 To solve for the selling price, we can divide both sides by 92% (or multiply by the reciprocal of 92%, which is 100/92): selling price = $117,760.00 ÷ 0.92 Using a calculator, we get: selling price = $128,000.00 Therefore, the selling price of the house was $128,000.00.

In the diagram, O is the centre of the circle of radius 18cm. If < zxy = 70\(^o\), calculate the length of arc ZY. [Take \(\pi = \frac{22}{7}\)]
 

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A box contains 3 white and 3 blue identical balls. If two balls are picked at random from the box, one after the other with replacement, what is the probability that they are of different colours?

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Bala sold an article for #6,900.00 and made a profit of 15%. Calculate his percentage profit if he had sold it for N6,600.00. 

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If Bala sold an article for #6,900.00 and made a profit of 15%, this means that his cost price for the article was lower than the selling price by 15%. We can calculate his cost price as follows: Cost Price = Selling Price / (1 + Profit%) Cost Price = 6,900 / (1 + 0.15) Cost Price = 6,000 Therefore, Bala's cost price was #6,000.00, and he sold the article for #6,900.00, making a profit of #900.00. Now, we need to calculate the percentage profit he would have made if he sold the article for #6,600.00 instead of #6,900.00. To do this, we can use the following formula: Percentage Profit = (Profit / Cost Price) x 100% Percentage Profit = (6,600 - 6,000) / 6,000 x 100% Percentage Profit = 10% Therefore, if Bala had sold the article for #6,600.00 instead of #6,900.00, he would have made a profit of 10%. The correct option is 10%.

In the diagram, PQ is parallel to RS, < QFG = 105\(^o\) and < FEG = 50\(^o\). Find the value of m.

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A box contains 5 red, 6 green and 7 yellow pencils of the same size. What is the probability of picking a green pencil at random?

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There are 5 + 6 + 7 = 18 pencils in the box. Since there are 6 green pencils, the probability of picking a green pencil at random is 6/18, which simplifies to 1/3. Therefore, the answer is \(\frac{1}{3}\).

If T = {prime numbers} and M = {odd numbers} are subsets of \(\mu\)  = {x : 0 < x ≤ 10} and x is an integer, find (T\(^{\prime}\) n M\(^{\prime}\)). 

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The set T is the set of prime numbers less than or equal to 10, which are {2, 3, 5, 7}. The prime complement (T\(\prime\)) is the set of non-prime numbers less than or equal to 10, which are {1, 4, 6, 8, 10}. The set M is the set of odd numbers less than or equal to 10, which are {1, 3, 5, 7, 9}. The odd complement (M\(\prime\)) is the set of even numbers less than or equal to 10, which are {2, 4, 6, 8, 10}. Finally, the intersection of T\(\prime\) and M\(\prime\) is the set of numbers that are both non-prime and even, which is {4, 6, 8, 10}. So (T\(\prime\) n M\(\prime\)) = {4, 6, 8, 10}.

The pie chart represents fruits on display in a grocery shop. If there are 60 oranges on display, how many apples are there?  
 

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Make b the subject of the relation lb = \(\frac{1}{2}\) (a + b)h

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Find the equation of a straight line passing through the point (1, -5) and having gradient of \(\frac{3}{4}\) 

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The fourth term of an Arithmetic Progression (A.P) is 37 and the first term is -20. Find the common difference.
 

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In an arithmetic progression (AP), the terms are equally spaced. Let's call the common difference "d". If we have the first term "a" and the nth term "an", we can find the common difference using the formula: d = (an - a) / (n - 1) In this case, the fourth term is 37 and the first term is -20, so we can plug in the values into the formula: d = (37 - (-20)) / (4 - 1) = 57 / 3 = 19 So the common difference is 19.

The interior angles of a polygon are 3x\(^o\), 2x\(^o\), 4x\(^o\), 3x\(^o\) and 6\(^o\). Find the size of the smallest angle of the polygon.

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If (0.25)\(^y\) = 32, find the value of y.

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We can solve the given equation by taking the logarithm of both sides. Any base of the logarithm can be used, but we will use the common logarithm (base 10). log\((0.25)^y\) = log 32 Using the logarithmic identity log\((a^b)\) = b log\((a)\), we get: y log\((0.25)\) = log 32 Now, we can evaluate log\((0.25)\) using the logarithmic identity log\((a^n)\) = n log\((a)\), as follows: log\((0.25)\) = log\((\frac{1}{4})\) = log\((4^{-1})\) = -log\((4)\) We know that log\((10^x)\) = x, so log\((4)\) = log\((10^{0.602})\) \(\approx\) 0.602 Therefore, y log\((0.25)\) = log 32 y (-log\((4)\)) = log 32 y (-0.602) = log 32 y = \(\frac{\text{log } 32}{-0.602}\) Using a calculator, we get: y \(\approx\) -2.5 Therefore, the value of y is approximately -2.5. Hence, the answer is: y = -\(\frac{5}{2}\).

If 7 + y = 4 (mod 8), find the least value of y, 10 \(\leq y \leq 30\) 

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Which of these values would make \(\frac{3p^-}{p^{2-}}\) undefined? 

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The following are scores obtained by some students in a test, Find the mode of the distribution  

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To find the mode of the distribution, we need to determine the value that appears most frequently in the dataset. Looking at the table, we can see that the value "13" appears three times, which is more than any other value. Therefore, the mode of this distribution is 13. Alternatively, we could create a frequency table or a histogram to visualize the distribution and identify the mode more easily.

If m : n = 2 : 1, evaluate \(\frac{3m^2 - 2n^2}{m^2 + mn}\)

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Simplify, correct to three significant figures, (27.63)\(^2\) - (12.37)\(^2\) 

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We can start by squaring each of the numbers in the expression: (27.63)\(^2\) = 762.9869 (12.37)\(^2\) = 153.4369 Now we can subtract the two squares: 762.9869 - 153.4369 = 609.55 Rounding the result to three significant figures, we get: 609.55 = 610 So (27.63)\(^2\) - (12.37)\(^2\) = 610.

The foot of a ladder is 6m from the base of an electric pole. The top of the ladder rest against the pole at a point 8m above the ground. How long is the ladder? 

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To find the length of the ladder, we can use the Pythagorean theorem, which states that in a right triangle, the square of the hypotenuse (the longest side) is equal to the sum of the squares of the other two sides. In this case, the ladder is the hypotenuse, and the distance from the foot of the ladder to the pole and the height of the pole where the ladder is resting form the other two sides of the right triangle. So we have: Length of ladder^2 = (distance from foot of ladder to pole)^2 + (height of pole where ladder is resting)^2 Length of ladder^2 = 6^2 + 8^2 Length of ladder^2 = 36 + 64 Length of ladder^2 = 100 Length of ladder = √100 = 10 Therefore, the length of the ladder is 10 meters. Answer option C (10m) is correct.

If 6, P, and 14 are consecutive terms in an Arithmetic Progression (AP), find the value of P.

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In an arithmetic progression (AP), the difference between any two consecutive terms is constant. So, we can find the common difference (d) between any two consecutive terms in the given AP by subtracting one term from the preceding term. Let's use the second term (P) and the first term (6) to find the common difference: d = P - 6 Now, to check whether 14 is the third term of the AP, we can use the formula for the nth term of an AP: an = a1 + (n-1)d where an = nth term a1 = first term d = common difference If 14 is the third term, then n = 3, so we have: 14 = 6 + (3-1)d 14 = 6 + 2d 2d = 8 d = 4 Now, we can substitute the value of d in the expression we got earlier: d = P - 6 4 = P - 6 P = 10 Therefore, the value of P is 10.

In the diagram, RT is a tangent to the circle at R, < PQR = 70\(^o\), < QRT = 52\(^o\), < QSR and < PRQ = x. Calculate the value of x.

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8, 18, 10,14, 18, 11, 13, 14, 13, 17, 15, 8, 16, and 13

The following are scores obtained by some students in a test. How many students scored above the mean score? 

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Solve: \(\frac{y + 1}{2} - \frac{2y - 1}{3}\) = 4

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To solve this equation, we can start by simplifying both sides by finding a common denominator. \(\frac{y + 1}{2} - \frac{2y - 1}{3} = 4\) Multiplying the first term by 3 and the second term by 2 (the least common multiple of 2 and 3), we get: \(\frac{3(y+1)}{6} - \frac{2(2y-1)}{6} = 4\) Simplifying this gives: \(\frac{3y + 3 - 4y + 2}{6} = 4\) Combining like terms: \(\frac{-y + 5}{6} = 4\) Multiplying both sides by 6: \(-y + 5 = 24\) Subtracting 5 from both sides: \(-y = 19\) Finally, multiplying both sides by -1 to solve for y: \(y = -19\) Therefore, the solution is y = -19.

If log\(_x\) 2 = 0.3, evaluate log\(_x\) 8.

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We can use the property of logarithms that states: $$\log_{a}(b^c) = c \log_{a}(b)$$ Using this property, we can rewrite the expression for log\(_x\) 8 as: $$\log_{x}(8) = \log_{x}(2^3) = 3\log_{x}(2)$$ We are given that log\(_x\) 2 = 0.3, so we can substitute this value: $$3\log_{x}(2) = 3(0.3) = 0.9$$ Therefore, the value of log\(_x\) 8 is 0.9. Therefore, option (C) is the correct answer: 0.9.

H varies directly as p and inversely as the square of y. If H = 1, p = 8 and y = 2, find H in terms of p and y.

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Simplify: \(\log_{10}\) 6 - 3 log\(_{10}\)  3 + \(\frac{2}{3} \log_{10} 27\)

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In the diagram, RT is a tangent to the circle at R, < PQR = 70\(^o\), < QRT = 52\(^o\), < QSR and < PRQ = x. Find the value of y. 

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If 2\(^{a}\) = \(\sqrt{64}\) and \(\frac{b}{a}\) = 3, evaluate a\(^2 + b^{2}\) 

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First, let's solve for a using the given equation 2\(^{a}\) = \(\sqrt{64}\). We know that \(\sqrt{64}\) is equal to 8, so we can substitute this value in the equation: 2\(^{a}\) = 8 To solve for a, we need to find the exponent that 2 is raised to in order to get 8. This exponent is 3, so a = 3. Next, we need to find the value of b. We are given that \(\frac{b}{a}\) = 3, so we can rearrange this equation to solve for b: b = 3a Substituting the value we found for a, we get: b = 3 x 3 = 9 Finally, we can evaluate a\(^2\) + b\(^2\) using the values we found for a and b: a\(^2\) + b\(^2\) = 3\(^2\) + 9\(^2\) = 9 + 81 = 90 Therefore, the answer is 90.

A rectangular board has a length of 15cm and width x cm. If its sides are doubled, find its new area.

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Let's first find the area of the original rectangular board, which is simply the product of its length and width: original area = 15 cm x x cm = 15x cm\(^2\) When the sides are doubled, the length becomes 15 cm x 2 = 30 cm, and the width becomes x cm x 2 = 2x cm. So, the new area is: new area = 30 cm x 2x cm = 60x cm\(^2\) So, the new area of the rectangular board is 60x cm\(^2\).

Simplify: \(\frac{x^2 - 5x - 14}{x^2 - 9x + 14}\) 

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To simplify the fraction, we need to find a common denominator for the numerator and denominator. The denominator, \(x^2 - 9x + 14\), can be factored into the product of two binomials: \((x - 7)(x - 2)\). Now, to simplify the numerator, we can factor it as well: \(x^2 - 5x - 14 = (x - 7)(x + 2)\). With this factoring, we can cancel out the common factor of \(x - 7\) in the numerator and denominator, leaving us with the simplified fraction: \(\frac{x^2 - 5x - 14}{x^2 - 9x + 14} = \frac{(x - 7)(x + 2)}{(x - 7)(x - 2)} = \frac{x + 2}{x - 2}\). So the simplified fraction is.

Evaluate: \(\frac{0.42 + 2.5}{0.5 \times 2.95}\), leaving the answer in the standard form.

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To solve this expression, we need to follow the order of operations which is parentheses, exponents, multiplication and division (from left to right), and addition and subtraction (from left to right). We do not have any parentheses or exponents, so we can proceed to the multiplication and division step. We have: \[\frac{0.42 + 2.5}{0.5 \times 2.95} = \frac{2.92}{1.475}\] Next, we can simplify the fraction by dividing both the numerator and denominator by the greatest common factor which is 0.05. \[\frac{2.92}{1.475} = \frac{292}{147.5}\] Finally, we can express this fraction in standard form by moving the decimal point in the numerator to the left by two places and simultaneously moving the decimal point in the denominator to the left by two places. \[\frac{292}{147.5} = 1.98\] Therefore, the answer is 1.639 x 10\(^1\) in standard form.

From the top of a vehicle cliff 20m high, a boat at sea can be sighted 75m away and on the same horizontal position as the cliff. Calculate, correct to the nearest degree, the angle of depression of the boat from the top of the cliff. 

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The situation can be represented by the following diagram: ``` A /| / | 20m / | B---C 75m ``` Where A is the top of the cliff, B is the boat, and C is the point on the cliff directly above the boat. We want to find the angle of depression, which is the angle ACB. We can use trigonometry to find this angle. First, we need to find the length of AC. This is simply the height of the cliff, which is given as 20m. Next, we need to find the length of BC. This is the horizontal distance from the base of the cliff to the boat, which is given as 75m. Now we can use the tangent function to find the angle of depression: tan(ACB) = opposite / adjacent = 20 / 75 Taking the inverse tangent (or arctan) of both sides gives: ACB = arctan(20 / 75) = 15.02 degrees (to two decimal places) Therefore, the angle of depression of the boat from the top of the cliff is approximately 15 degrees (to the nearest degree). So the answer is option D: 15\(^o\).

The following are scores obtained by some students in a test. Find the median score 
 

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In the diagram, RT is a tangent to the circle at R, < PQR = 70\(^o\), < QRT = 52\(^o\), < QSR and < PRQ = x.  Calculate the variance of 2, 4, 7, 8 and 9 

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There are 8 boys and 4 girls in a lift. What is the probability that the first person who steps out of the lift will be a boy? 

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The probability of an event happening is the number of ways it can happen divided by the total number of outcomes. In this case, there are 8 boys and 4 girls in the lift. If the first person who steps out of the lift is a boy, it means that any one of the 8 boys can be the first person to step out of the lift. Therefore, the number of ways the event can happen is 8. The total number of outcomes is the total number of people who can step out of the lift first. Since there are 12 people in the lift, any one of the 12 people can be the first person to step out of the lift. Therefore, the total number of outcomes is 12. Therefore, the probability that the first person who steps out of the lift will be a boy is: probability = number of ways the event can happen / total number of outcomes probability = 8 / 12 probability = 2 / 3 Hence, the answer is: \(\frac{2}{3}\).

(a) The third and sixth terms of a Geometric Progression (G.P) are and \(\frac{1}{4}\) and \(\frac{1}{32}\) respectively.

Find:

(i) the first term and the common ratio;

(ii) the seventh term.

(b) Given that 2 and -3 are the roots of the equation ax\(^2\) ± bx + c = 0, find the values of a, b and c. 

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(a) (i) The first term and the common ratio of a Geometric Progression (G.P) can be found using the formula for the nth term of a G.P:

a_n = a * r^(n-1)

where a is the first term, r is the common ratio, and n is the term number.

We are given that the third term is 1/4 and the sixth term is 1/32. We can use these values to solve for a and r:

a * r^(3-1) = 1/4

a * r^(6-1) = 1/32

Dividing the second equation by the first:

a * r^(6-1) / a * r^(3-1) = 1/32 / 1/4

r³ = 1/32 / 1/4

r³ = (1/32) * (4)

r³ = 1

Taking the cube root of both sides:

r = 1^(1/3) = 1

Substituting r = 1 back into the first equation:

a * 1^(3-1) = 1/4

a = 1/4

So, the first term is 1/4 and the common ratio is 1.

(ii) To find the seventh term, we can use the formula for the nth term of a G.P:

a_n = a * r^(n-1)

where a is the first term (1/4), r is the common ratio (1), and n is the term number (7).

a₇ = 1/4 * 1^(7-1) = 1/4 * 1⁶ = 1/4 * 64 = 16

So, the seventh term is 16.

(b) Given that 2 and -3 are the roots of the equation ax² + bx + c = 0, we can use the sum and product of the roots formula to find the values of a, b, and c:

The sum of the roots = -b/a

The product of the roots = c/a

Since we are given that the roots are 2 and -3, we can substitute:

The sum of the roots = 2 + (-3) = -1

The product of the roots = 2 * (-3) = -6

So:

-b/a = -1

c/a = -6

Multiplying both equations by a:

-b = -a

c = -6a

Since a is non-zero, we can divide both equations by -1 to simplify:

b = a

c = -6

(a) Find the equation of the line which passes through the points A(-2, 7) and B(2, -3)

(b) Given that \(\frac{5b - a}{8b + 3a} = \frac{1}{5}\) = find, correct to two decimal places, the value \(\frac{a}{b}\)
 

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a) To find the equation of the line that passes through two points A and B:

The slope-point form of a line is given by:

y - y1 = m(x - x1)

where m is the slope of the line and (x1, y1) is a point on the line. The slope of the line can be found using the formula:

m = (y2 - y1) / (x2 - x1)

Substituting the values of x1, y1, x2, and y2, we get:

m = (-3 - 7) / (2 - (-2)) = -10 / 4 = -5/2

So, the equation of the line in slope-point form becomes:

y - 7 = -5/2 (x + 2)

Expanding the right-hand side, we get:

y - 7 = -5/2 x - 5

Adding 5 to both sides, we get:

y - 2 = -5/2 x

Dividing both sides by -5/2, we get:

2x + y = 9

This is the equation of the line that passes through the points A(-2, 7) and B(2, -3).

b) To solve for a/b:

We need to rearrange the equation:

\(\frac{5b - a}{8b + 3a} = \frac{1}{5}\)

Multiplying both sides by 8b + 3a, we get:

5b - a = \(\frac{8b + 3a}{5}\)

Expanding the right-hand side, we get:

5b - a = \(\frac{8b}{5} + \frac{3a}{5}\)

Subtracting \(\frac{8b}{5}\) from both sides, we get:

-3b + a = \(\frac{3a}{5}\)

Multiplying both sides by 5, we get:

-15b + 5a = 3a

Subtracting 3a from both sides, we get:

-15b + 2a = 0

Dividing both

The data shows the marks obtained by students in a biology test

(a) Construct a frequency distribution table  using the class interval 0 - 9, 10 - 19, 19, 20, 29... 

(b) Draw a cumulative frequency curve for the distribution 

(c) Use the graph to estimate the;

(i) median

(ii) Percentage of students who scored at least 66 marks, correct to the nearest whole number.

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a)

b)

(c)

(i) Mean mark

= 49.9

(ii) Percentage of at least 66 mark

= 1350×100 $\frac{13}{50}\times 100$%

= 26%

(a) Fred bought a car for $5,600.00 and later sold it at 90% of the cost price. He spent $1,310.00 out of the amount received and invested the rest at 6% per annum simple interest. Calculate the interest earned in 3 years.

(b) Solve the equations 2\(^x\)(4\(^{-7}\)) = 2 and 3\(^{-x}\)(9\(^{2y}\)) = 3 simultaneously.
 

Antwoorddetails

a) First, let's calculate the amount Fred received after selling the car. He sold the car for 90% of its cost price, so he received $5,600 * 0.9 = $5,040.00. After spending $1,310.00, he was left with $5,040 - $1,310 = $3,730.00. This is the amount he invested at 6% per annum simple interest.

The formula for simple interest is I = P * R * T, where I is the interest, P is the principal (the amount invested), R is the rate of interest (as a decimal), and T is the time (in years). Plugging in the values, we have I = $3,730 * 0.06 * 3 = $676.20.

So Fred earned $676.20 in interest over a period of 3 years.

b) To solve the equations 2^x(4^-7) = 2 and 3^-x(9^2y) = 3 simultaneously, we need to find the values of x and y that make both equations true.

Starting with the first equation, we can simplify the left-hand side to get 2^x * 4^-7 = 2^x * (1/16) = 2. We can then divide both sides of the equation by 2^x to get (1/16) = 1. Since this is not true, there are no values of x that make this equation true.

Next, let's simplify the second equation to get 3^-x * 9^2y = 3^-x * 81^y = 3. Dividing both sides of the equation by 3^-x gives us 81^y = 3^x. Taking the log base 3 of both sides gives us y = x.

So the only solution for x and y is x = y = 1.

In conclusion, there is only one solution for the system of equations, x = y = 1.

NOT DRAWN TO SCALE

In the diagram, is a chord of a circle with centre 0. 22.42 cm and the perimeter of triangle MON is 55.6 cm. Calculate, correct to the nearest degree. < MON.

(b) T is equidistant from P and Q. The bearing of P from T is 60\(^o\) and the bearing of Q from T is 130\(^o\).

(i) Illustrate the information on a diagram.

(ii) Find the bearing of Q from P.

Antwoorddetails

(a) To solve this problem, we need to use the following formula: Perimeter of triangle MON = MO + ON + NM We know that the perimeter of triangle MON is 55.6 cm. Let's assume that MO = x, ON = y, and NM = z. Then we have: x + y + z = 55.6 We also know that MO and ON are radii of the circle, so they are equal in length. Let's assume that MO = ON = r. Then we have: x + y = 2r We can rearrange this equation to get: r = (x + y) / 2 Now let's look at the chord PQ. We know that the perpendicular bisector of a chord passes through the centre of the circle. Let's draw a line from the centre of the circle to the midpoint of PQ and label it M. We also know that MO is a radius of the circle, so MO = r. Let's label the distance from M to the midpoint of PQ as d. Then we have: r^2 = d^2 + (PQ/2)^2 We know that PQ = 22.42 cm, so we can substitute that in: r^2 = d^2 + 250 We can rearrange this equation to get: d^2 = r^2 - 250 Now we have two equations with two unknowns (x and y), and one equation (d^2 = r^2 - 250) that relates them. We can substitute r = (x + y) / 2 into the equation for d^2: d^2 = ((x + y) / 2)^2 - 250 Simplifying this equation gives: d^2 = (x^2 + 2xy + y^2) / 4 - 250 Multiplying both sides by 4 gives: 4d^2 = x^2 + 2xy + y^2 - 1000 We also know that x + y = 2r, so we can substitute that in: 4d^2 = x^2 + 4xr + y^2 - 1000 Substituting r = (x + y) / 2 gives: 4d^2 = x^2 + 4x((x+y)/2) + y^2 - 1000 Simplifying this equation gives: 4d^2 = 5x^2 + 10xy + 5y^2 - 1000 We can now substitute x + y = 2r and simplify: 4d^2 = 5x^2 + 10xr + 5r^2 - 1000 Substituting r^2 = d^2 + 250 gives: 4d^2 = 5x^2 + 10xd^2/(x+y) + 5d^2 + 1250 Simplifying this equation gives: 4d^2 = 5x^2(x+y) + 10xd^2 + 5d^2(x+y) + 1250(x+y) We know that x + y + z = 55.6, so we can substitute z = 55.6 - x - y into the equation for the perimeter of triangle MON: x + y + z = 55.6 z = 55.6 - x - y Substituting this into the equation for MO + ON + NM gives: r + r + z = 55.6 2r + z = 55.6 2r = 55.6 - z r

The second, fourth and sixth terms of an Arithmetic Progression (AP.) are x - 1, x + 1 and 7 respectively. Find the:

(a) common difference;

(b) first term;

(c) value of x.

 

Antwoorddetails

An Arithmetic Progression (AP) is a sequence of numbers where the difference between any two consecutive terms is always the same. If a, b, c are three terms of an AP, then b - a = c - b. This common difference is denoted by d.

In this problem, we are given the second, fourth, and sixth terms of the AP as x - 1, x + 1, and 7 respectively. We can use these terms to find the common difference d and the first term a.

Let's call the first term a. Then, the second term a + d = x - 1, the fourth term a + 3d = x + 1, and the sixth term a + 5d = 7. We can use these equations to find d and a.

From the equation a + d = x - 1, we get d = x - 1 - a.

Substituting this in a + 3d = x + 1, we get a + 3(x - 1 - a) = x + 1
Expanding the brackets, we get a + 3x - 3 - 3a = x + 1
Combining like terms, we get -2a + 3x - 2 = x + 1
Solving for x, we get x = (2a + 2)/2

Substituting this value of x in d = x - 1 - a, we get d = (2a + 2)/2 - 1 - a = (2 - 2a)/2

Finally, substituting this value of d in a + 5d = 7, we get a + 5(2 - 2a)/2 = 7
Expanding the brackets, we get a + 5 - 5a = 7
Combining like terms, we get -4a + 5 = 7
Solving for a, we get a = 2.

So, the common difference d is 2 - 2a = 2 - 2 * 2 = -2, and the first term a is 2.

The value of x can be found from x = (2a + 2)/2 = (2 * 2 + 2)/2 = (4 + 2)/2 = 6/2 = 3.

Hence, the common difference is -2, the first term is 2, and the value of x is 3.

Three red balls, five green balls, and a number of blue balls are put together in a sack. One ball is picked at random from the sack. If the probability of picking a red ball is \(\frac{1}{6}\) find;

(a) The number of blue balls in the sack 

(b) the probability of picking a green ball

Antwoorddetails

(a) Let the number of blue balls be x.

The probability of picking a red ball is 1/6, which means there is only one red ball in the sack.

Therefore, the total number of balls in the sack is:

1 (red ball) + 5 (green balls) + x (blue balls) = 6 + x

The probability of picking a red ball is the number of red balls in the sack divided by the total number of balls in the sack. So we can write:

1/(6 + x) = 1/6

Solving for x, we get:

6 + x = 6

x = 0

Therefore, there are 0 blue balls in the sack.

(b) The probability of picking a green ball is the number of green balls in the sack divided by the total number of balls in the sack.

Since we know there are 5 green balls and 1 red ball in the sack (and 0 blue balls, as we found in part (a)), the total number of balls in the sack is:

1 (red ball) + 5 (green balls) + 0 (blue balls) = 6

So the probability of picking a green ball is:

5/6

Therefore, the probability of picking a green ball is 5/6.

(a) Copy and complete the table of values for the relation y = 4x\(^2\) - 8x - 21, for -2.0 \(\leq\) x \(\leq\) 4.0 

(b) Using a scale of 2cm to 1 unit on the x-axis and 2cm to 5 units on the y-axis, draw the graph for the relation y = 4x\(^2\) - 8x - 21

(ii) Use the graph to find the solution set of 

(\(\alpha\)) 4x\(^2\) - 8x = 3;

(\(\beta\)) 4x\(^2\) - 7x - 21 = 0

Antwoorddetails

I'm sorry, I'm an AI language model and I don't have the ability to draw graphs. However, I can help you complete the table of values and explain how to find the solution sets for the given equations.

For part (a), to complete the table of values, you need to substitute each value of x in the equation y = 4x² - 8x - 21 and calculate the corresponding value of y.

For part (ii), to find the solution set for 4x² - 8x = 3, you can isolate x by adding 8x to both sides and then dividing both sides by 4. This gives you x² = x + 11/4. To find the solution set for 4x² - 7x - 21 = 0, you can factor the equation or use the quadratic formula to find the two roots.

In both cases, the solution set consists of the x-values that make the equation true. These x-values can then be plotted on the graph to find the corresponding y-values.

In the diagram, PQRS is a quadrilateral, < PQR = < PRS = 90\(^o\), |PQ| =3cm, |QR| = 4cm and |PS| = 13 cm. Find the area of the quadrilateral. 

Antwoorddetails

We can use the Pythagorean theorem to find the length of the diagonal PR and then use the formula for the area of a parallelogram to find the area of the quadrilateral.

The Pythagorean theorem states that in a right triangle, the sum of the squares of the lengths of the two smaller sides is equal to the square of the length of the longest side, which is the hypotenuse. In this case, the right triangle is PQR, so we have:

PQ² + QR² = PR²

Substituting the given values, we get:

3² + 4² = PR²

9 + 16 = PR²

25 = PR²

PR = sqrt(25) = 5

Now that we have the length of the diagonal PR, we can find the area of the parallelogram using the formula:

Area = base * height

Since PR is the height of the parallelogram, we can use any of the sides of the quadrilateral as the base. Let's use PQ as the base:

Area = PQ * PR

Area = 3 * 5

Area = 15 square cm

So the area of the quadrilateral is 15 square cm.

(a) Solve the inequality: \(\frac{1 + 4x}{2}\) -\(\frac{5 + 2x}{7}\) < x -2

(b) If x: y = 3: 5, find the value of \(\frac{2x^2 - y^2}{y^2 - x^2}\)

Antwoorddetails

(a)

majority of the candidates multiplied through by the L.C.M which is 14 to arrive at

7(1+4x) - 2(5+2x) < 14(x - 2)

and when simplified yielded

10x < -25 x -212 $\frac{1}{2}$

(b)

it was expected that they express

x = 3y5 $\frac{3𝑦}{5}$ or y = 5x3 $\frac{5𝑥}{3}$ 

and thereafter, substitute into the given expression to have 

2x2−y2y2−x2=2x2−(5x3)2(5x3)2−x2=x(2−259)x2(259−1)

=−716

(a) Solve the inequality 13x?14(x+2)?3x?113 $\frac{\mathrm{<br>}}{}$

(b) 

In the diagram, ABC is right-angled triangle on a horizontal ground. |AD| is a vertical tower. < BAC = 90o ${}^{?}$, < ACB = 35o ${}^{?}$, < ABD = 52o ${}^{?}$ and |BC| = 66cm.

Antwoorddetails

13x−14(x+2)≥3x−113 $\frac{\mathrm{<br>}}{}$

13x−(x+2)12≥3x−43 $\frac{\mathrm{<br>}}{}$

4x−3x−612≥3x−43 $\frac{4𝑥-3𝑥-6}{12}\ge 3𝑥-\frac{4}{3}$

x−612≥3x1−43 $\frac{𝑥-6}{12}\ge \frac{3𝑥}{1}-\frac{4}{3}$

x−612≥9x−43 $\frac{𝑥-6}{12}\ge \frac{9𝑥-4}{3}$ 

3(x - 6) ≥ $\ge$ 12(9x - 4)

3x - 18 ≥ $\ge$ 108x - 48

3x - 108x ≥ $\ge$ -48 + 18

−105x−105≥−30−105 $\frac{-105𝑥}{-105}\ge \frac{-30}{-105}$ 

x ≥1035 $<br>\frac{\mathrm{<br>}}{}$

x 
$\ge$ 27

 27

(b)

(i) 

CB $𝐵$A = 108o ${}^{𝑜}$ - (90o ${}^{𝑜}$ + 35o ${}^{𝑜}$)

= 180o ${}^{𝑜}$ - 125o ${}^{𝑜}$ = 55o

sin35o ${}^{𝑜}$ = |AB|66 $\frac{|𝐴𝐵|}{66}$

|AB| = 66 x sin30o ${}^{𝑜}$ 

|AB| = 37.856m

cos 35o ${}^{𝑜}$ = |AC|66 $\frac{|𝐴𝐶|}{66}$

|AC| = 66 x cos35o ${}^{𝑜}$ 

|AC| = 55.06m

Tan52o ${}^{𝑜}$ = |AD|37.856 $\frac{|𝐴𝐷|}{37.856}$

|AD| = 37.856 x Tan52o ${}^{𝑜}$

= 48.45m the height of the tower to 2d.p

(ii)

Tan AC $𝐶$D = 48.45354.06

=0.8962

AC $𝐶$D = tan−1 ${}^{-1}$0.8962

= 41.867o ${}^{𝑜}$

Angle of elevation of the tower from

C = 35o ${}^{𝑜}$ + 41.867o ${}^{𝑜}$ 

= 76.87o ${}^{𝑜}$ to 2d.p

(a) Without using mathematical tables or calculator, simplify: \(\frac{log_28 + \log_216 - 4 \log_22}{\log_416}\)

(b) If 1342\(_{five}\) - 241\(_{five}\) = x\(_{ten}\), find the value of x.
 

Antwoorddetails

a. To simplify the expression, we can use the properties of logarithms:

• log_a + log_b = log_ab
• log_a - log_b = log_(a/b)
• log_aⁿ = n log_a

Using these properties, we can simplify the expression as follows:

\(\frac{{\log_2 8 + \log_2 16 - 4 \log_2 2}}{{\log_4 16}}\)

= \(\frac{{3 + 4 - 4(1)}}{2}\) since log base 2 of 8 is equal to 3, log base 2 of 16 is equal to 4, and log base 2 of 2 is equal to 1.

= \(\frac{3}{2}\)

Therefore, \(\frac{{\log_2 8 + \log_2 16 - 4 \log_2 2}}{{\log_4 16}}\) simplifies to \(\frac{3}{2}\).

b. 1342_five means 1*(5^3) + 3*(5^2) + 4*(5^1) + 2*(5^0) in base 10, which equals 125 + 75 + 20 + 2 = 222.

241_five means 2*(5^2) + 4*(5^1) + 1*(5^0) in base 10, which equals 50 + 20 + 1 = 71.

Therefore, 1342_five - 241_five in base 10 equals 222 - 71 = 151.

Since the question asks us to find the value of x_ten, which is the base 10 representation of the result, we have x_ten = 151.

The cost of dinner for a group of tourist is partly constant and partly varies as the number of tourists present. It costs $740.00 when 20 tourists were present and $960.00 when the number of tourists increased by 10. Find the cost of the dinner when only 15 tourists were present.