What is the average number of girls in School $A$ in all the years taken together ?
(a)760
(b)800
(c)860
(d)600
(e)None of these
Answer
Answer (as printed): C
Explanation
Average number of girls in School $A$ over the years $$\begin{aligned} & =\frac{(3.6+4.2+6.9+9.6+12.9+14.4) \times 100}{6} \\ & =\left(\frac{51.6 \times 100}{6}\right)=\frac{5160}{6}=860 . \end{aligned}$$
Explanation as extracted from the printed page; notation may be imperfect.