### The average of five numbers is 7. When three new numbers are included, the average of the eight numbers becomes 8.5. The average of the three new numbers is :

A. 9 B. 10.5 C. 11 D. 11.5 Answer: Option C

### Solution(By Apex Team)

Sum of 5 numbers = 7 × 5 = 35 Sum of 8 numbers = 8.5 × 8 = 68 Sum of added all three numbers = 68 – 35 = 33 Average of three new numbers $\begin{array}{l}=\Large\frac{33}{3}\\ =11\end{array}$

A. 20
B. 21
C. 28
D. 32

A. 18
B. 20
C. 24
D. 30

A. 10 years
B. 10.5 years
C. 11 years
D. 12 years