Question

The mean of $10$ numbers is $24$. If one more number is included, the new mean is $25$. Find the included number.

• A. $28$
• B. $32$
• C. $35$
• D. $40$

Answer 1

The correct option is C $35$

mean of $10$ numbers = $24$
Sum of $10$ numbers = $24\times 10$ = $240$
After including one number,
mean of $11$ numbers = $25$
Sum of $11$ numbers = $25\times 11$ = $275$
Thus, the number excluded = $275-240=35$