Question

The mean of $5$ numbers is $20$. If one number is excluded, mean of the remaining numbers becomes $23$, then the excluded number is ______.

• A. $4$
• B. $92$
• C. $100$
• D. $8$

Answer 1

Answer: (D)

$8$

Let the excluded number be $x$.
Sum of $5$ numbers $=20\times 5=100$
After excluding $x$.
Sum of $4$ numbers $=4\times 23=92$
Therefore, $x=100-92$
$\Rightarrow x=8$