### 16 children are to be divided into two groups A and B of 10 and 6 children. The average percent marks obtained by the children of group A is 75 and the average percent marks of all the 16 children is 76. What is the average percent marks of children of group B ?

A. $77 \Large\frac{1}{3}$ B. $77 \Large\frac{2}{3}$ C. $78 \Large\frac{1}{3}$ D. $78 \Large\frac{2}{3}$ Answer: Option B

### Solution(By Apex Team)

\begin{aligned}&\text{ Required average }\\ &=\frac{(76\times16)-(75\times10)}{6}\\ &=\left(\frac{1216-750}{6}\right)\\ &=\frac{466}{6}\\ &=\frac{233}{3}\\ &=77\frac{2}{3}\end{aligned}

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