Question

Find the mean of first $10$ multiples of $3$.

• A. $14.5$
• B. $13$
• C. $16.5$
• D. $23$

Answer 1

Answer: (C)

$16.5$

First $10$ multiples of $3$ are $3,6,\mathrm{9...30}$.
This is an A.P.
$sum=\frac{n}{2}(a+l)=\frac{10}{2}\times (3+30)$
$\therefore sum=165$.
Mean, $u=\frac{sum}{n}=\frac{165}{10}$.
$\therefore u=16.5$
Ans-Option $C$.