Question

Mean of 21 values is 35. If a value is excluded the mean becomes 36. The excluded value is

• A. 15
• B. 20
• C. 35
• D. none of these

Answer 1

The correct option is A 15

$\Rightarrow$ Mean of $21$ values is $35$.

$\therefore$ Sum of $21$ numbers $=21\times 35=735$

$\Rightarrow$ When a value is excluded the mean becomes $36$, means mean value of $20$ numbers is $36$

$\therefore$ Sum of $20$ numbers $=20\times 36=720$

$\Rightarrow$ The excluded value $=$ Sum of $21$ numbers $-$Sum of $20$ numbers

$=735-720$

$=15$

$\therefore$ The excluded value is $15$.