Below are the scores of a group of students in a test: Scores123456No. of students1456x2 S c o r e s 1 2 3 4 5 6 No. of students 1 4 5 6 x 2 If the average ...

Answer Details

$\begin{array}{ccccccc}Scores& 1& 2& 3& 4& 5& 6\\ \text{No. of students}& 1& 4& 5& 6& x& 2\end{array}$
Average = 3.5
3.5 = $\frac{(1\times 1)+(2\times 4)+(3\times 5)+(4\times 6)+5x+(6\times 2)}{1+4+5+6+x+2}$
$\frac{3.5}{1}$ = $\frac{1+8+15+24+5x+12}{18+x}$
$\frac{3.5}{1}$ = $\frac{60+5x}{18+x}$
60 + 5x = 3.5(18 $÷$ x)
60 + 5x = = 63 + 1.5x
5x - 1.5x = 63 - 60
1.5x = 3
x = $\frac{3}{1.5}$
$\frac{30}{15}$ = 2