JAMB UTME - Mathematics - 1994

Answer Details

SQR + RQV + VQU = 18o angle on a straight line SP is parallel to QR and PV is parallel to TR

< STP = < RQV = 30o

But SQR + 30o + 50o = 180o

SQR = 180 - 80

= 100o

An open rectangular box is made of wood 2cm thick. If the internal dimensions of the box are 50cm long, 36cm wide and 20cm deep, the box volume of wood in the box is

Answer Details

Internal dimension are 50cm, 36cm and 20cm
internal volume = 50 x 36 x 20cm3
1000 x 36cm3
= 36000cm3
External dimension are 54cm x 40cm x 22cm
= 2160cm2 x 22cm = 47520cm3
Volume of wood = Ext. volume - Int. volume
= 47,520cm3 - 36,000cm3
= 11,520cm3

Find the point (x, y) on the Euclidean plane where the curve y = 2x2 - 2x + 3 has 2 as gradient

Answer Details

We know that the gradient of a curve is given by its derivative. Therefore, we need to find the derivative of the given curve and equate it to 2 to find the point where the gradient is 2. y = 2x^2 - 2x + 3 dy/dx = 4x - 2 Equating dy/dx to 2, we get: 4x - 2 = 2 4x = 4 x = 1 Substituting x = 1 in the original equation, we get: y = 2(1)^2 - 2(1) + 3 y = 3 Therefore, the point where the curve has a gradient of 2 is (1, 3). So, the correct option is: (1, 3).

In a survey, it was observed that 20 students read newspapers and 35 read novels. If 40 of the students read either newspapers or novels, what is the probability of the students who read both newspapers and novels?

Answer Details

40 = 20 - x + x + 35 - x
40 = 55 - x
x = 55 - 40
= 15
∴ P(both) $\frac{15}{40}$
= $\frac{3}{8}$

What is the locus of a point P which moves on one side of a straight line XY, so that the angle XPY is always equal to 90o?

Answer Details

Since XY is a fixed line and
XPY = 90o P is on one side of XY
P1P2P3......Pn are all possible cases where
XPY = 90o the only possible tendency is a semicircle because angles in semicircle equals 90o

Evaluate ${\int }_{-1}^1$(2x + 1)2dx

Answer Details

${\int }_{-1}^1$(2x + 1)2dx
= ${\int }_{-1}^1$(4x2 + 4x + 1)dx
= ${\int }_{-1}^1$[$\frac{4x^3}{3}$ + 2x2 + c]
= [$\frac{4}{3}$ + 3 + c] - [4 + $\frac{1}{3}$ + c]
= $\frac{8}{3}$ + 3 + -1 - C
= $\frac{8}{3}$ + 2
= $\frac{14}{3}$
= $\frac{42}{3}$

Find the mean deviation of the set of numbers 4, 5, 9

Answer Details

To find the mean deviation of a set of numbers, we first need to find the mean or average of those numbers. The mean of the numbers 4, 5, and 9 is: (mean) = (4 + 5 + 9) / 3 = 6 Next, we need to find the deviation of each number from the mean. To do this, we subtract the mean from each number: 4 - 6 = -2 5 - 6 = -1 9 - 6 = 3 To avoid positive and negative deviations cancelling out, we take the absolute value of each deviation: | -2 | = 2 | -1 | = 1 | 3 | = 3 Then, we find the mean of these absolute deviations by summing them up and dividing by the number of numbers: (2 + 1 + 3) / 3 = 2 Therefore, the mean deviation of the set of numbers 4, 5, 9 is 2. So, the correct option is 2.

Find the range of values of x for which 1x $\frac{1}{x}$ > 2 is true

Answer Details

1x $\frac{1}{x}$ > 2 = xx2 $\frac{x}{x^2}$ > 2

x > 2x2

= 2x2 < x

= 2x2 - x < 0

= x(2x - 10 < 0

Case 1(+, -) = x > 0, 2x - 1 < 0

x > 0, x < 12 $\frac{1}{2}$ (solution)

Case 2(-, 4) = x < 0, 2x - 1 > 0

x < 0, x , 12 $\frac{1}{2}$ = 0

Simplify $\sqrt{48}$ - $\frac{9}{\sqrt{3}}$ + $\sqrt{75}$

Answer Details

$\sqrt{48}$ - $\frac{9}{\sqrt{3}}$ + $\sqrt{75}$
Rearrange = $\sqrt{48}$ + $\sqrt{75}$ - $\frac{9}{\sqrt{3}}$
= (√16 x √3) + (√25 x √3) - $\frac{9}{\sqrt{3}}$
=4√3 + 5√3 - $\frac{9}{\sqrt{3}}$
Rationalize $\to$ 9√3 = $\frac{9}{\sqrt{3}}$ x $\frac{\sqrt{3}}{\sqrt{3}}$
= $\frac{9\sqrt{3}}{\sqrt{9}}$ - $\frac{9\sqrt{3}}{\sqrt{3}}$
= 3√3

In the diagram, PTS is a tangent to the circle TQR at T. Calculate < RTS

Answer Details

RTS = RQT (angle between a tangent and a chord at the point of contact is equal to the angle in the alternate segment) But R = Q + T = 180

RQT = 180${}^{?}$ - (50 + 60)

= 180${}^{?}$ - 110${}^{?}$

= 70${}^{?}$

Since RQT = RTS = 70${}^{?}$

Evaluate $\frac{0.36\times 5.4\times 0.63}{4.2\times 9.0\times 2.4}$

Answer Details

$\frac{0.36\times 5.4\times 0.63}{4.2\times 9.0\times 2.4}$
= $\frac{36}{420}\times \frac{54}{90}\times \frac{63}{240}$
= $\frac{6}{70}\times \frac{18}{30}\times \frac{21}{80}$
= $\frac{27}{2000}$
= 0.0135
$\approx$ = 0.013

The equation of the graph is

Answer Details

y = x3 - 27, y = -27 $\to$ (0, -27)

when y = 0, x = 3 (3, 0)

The mean of twelve positive numbers is 3. When another number is added, the mean becomes 5. Find the thirteenth number

Answer Details

Let the sum of the 12 numbers be x and the 13th number be y.

x12=3⟹x=36 $\frac{x}{12}=3⟹x=36$

36+y13=5⟹36+y=65 $\frac{36+y}{13}=5⟹36+y=65$

y=65−36=29

Simplify $\frac{(2m?u{)}^2?(m?2u{)}^2}{5m^2?5u^2}$

Answer Details

$\frac{(2m?u{)}^2?(m?2u{)}^2}{5m^2?5u^2}$
= $\frac{2m?u+m?2u\left)\right(2m?u?m+2u)}{5(m+u)(m?u)}$
= $\frac{3(m?u)(m+u)}{5(m+u)(m?u)}$
= $\frac{3}{5}$

Find the nth term of the sequence 3, 6, 10, 15, 21.....

Answer Details

$\frac{(n+1)(n+2)}{2}$
If n = 1, the expression becomes 3
n = 2, the expression becomes 6
n = 4, the expression becomes 15
n = 5, the expression becomes 21

$\begin{array}{cccccc}x& 1& 2& 3& 4& 5\\ f& y+2& y-2& 2y-3& y+4& 3y-4\end{array}$

This table shows the frequency distribution of a data if the mean is $\frac{43}{14}$ find y

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Given that for sets A and B, in a universal set E, A $?$ B then A $?$(A $?$ B)1 is

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A $\subset$ B means A is contained in B i.e. A is a subset of B(A $\cap$ B)1 = A1
A(A $\cap$ B)1 = A $\cap$ A1
The intersection of complement of a set P and P1 has no element
i.e. n(A $\cap$ A1) = $\varphi$

The grades A1, A2, A3, C4 and F earned by students in a particular course are shown in the pie chart. What percentage of the students obtained a C4 grade?

Answer Details

If y = 3t3 + 2t2 - 7t + 3, find $\frac{dy}{dt}$ at t = -1

Answer Details

y = 3t3 + 2t2 - 7t + 3
$\frac{dy}{dt}$ = 9t2 + 4t - 7
When t = -1
$\frac{dy}{dt}$ = 9(-1)2 + 4(-1) - 7
= 9 - 4 -7
= 9 - 11
= -2

The angle of depression of a boat from the top of a cliff 10m high is 30. How far is the boat from the foot of the cliff?

Answer Details

The given scenario can be visualized as follows:

          A (top of cliff)
          /|
         / |
        /  |
       /   | 10m
      /    |
     /θ    |   
    /      |
   /       |
  B--------C (boat on water surface)

Here, the angle of depression of point B from point A is given as 30 degrees. We are required to find the distance between point B and point C, denoted by BC.

We know that the tangent of an angle is the ratio of the opposite side to the adjacent side. In this case, the opposite side is AB and the adjacent side is BC.

Thus, we have:

tan 30° = AB / BC

AB is the height of the cliff, which is given as 10m.

Hence, we have:

1/√3 = 10 / BC

Solving for BC, we get:

BC = 10√3 meters

Therefore, the boat is 10√3 meters away from the foot of the cliff.

Hence, the answer is 10√3m.

Evaluate $\frac{1}{3}÷\left[\frac{5}{7}\right(\frac{9}{10}?1+\frac{3}{4}\left)\right]$

Answer Details

$\frac{1}{3}÷\left[\frac{5}{7}\right(\frac{9}{10}?1+\frac{3}{4}\left)\right]$
$\frac{1}{3}÷\left[\frac{5}{7}\right(\frac{9}{10}?\frac{10}{10}+\frac{3}{4}\left)\right]$
= $\frac{1}{3}÷\left[\frac{5}{7}\right(\frac{?1}{10}+\frac{3}{4}\left)\right]$
= $\frac{1}{3}÷\left[\frac{5}{7}\right(\frac{?2+15}{20}\left)\right]$
= $\frac{1}{3}÷[\frac{5}{7}\times \frac{13}{20}]$
$\frac{1}{3}+\left[\frac{13}{28}\right]$ = $\frac{1}{3}\times \frac{28}{13}$
= $\frac{28}{39}$

$\begin{array}{ccccc}\oplus mod10& 2& 4& 6& 8\\ 2& 4& 8& 2& 6\\ 4& 8& 6& 4& 2\\ 4& 8& 6& 4& 2\\ 6& 2& 4& 6& 8\\ 8& 6& 2& 8& 4\end{array}$

The multiplication table above has modulo 10 on the set S = (2, 4, 6, 8). Find the inverse of 2

Answer Details

The inverse of 2 is 6 since 2 x 6 = 12; under mod 10
12 = 2 which is also the value required