Question

The mean of five numbers is $18$. If one number is excluded, then their mean is $16$, the excluded number is ___________.

• A. $24$
• B. $26$
• C. $28$
• D. $25$

Answer 1

Answer: (B)

$26$

Mean of $5$ numbers $=18$

$\Rightarrow$ Sum of these $5$ numbers $=18\times 5=90$

Let number that has been excluded be $x$

New mean $=\frac{90-x}{4}=16$

Solving this, we get

$90-x=64$

$\therefore x=26$