Question

The mean of eleven numbers is $47$. If a number is added then mean is increased by $2$. Find the new number.

• A. $51$
• B. $61$
• C. $71$
• D. $81$

Answer 1

Answer: (C)

$71$

Mean of $11$ numbers $=$ $47$
Sum of $11$ numbers $=$ $11\times 47$ $=$ $517$
Let the new number added $=$ $x$
New mean ( $12$ numbers) $=$ $49$
Sum of $12$ numbers $=$ $49\times 12$ = $588$
Hence. $517+x$ $=$ $588$
$\Rightarrow x=71$