### Of four numbers whose average is 60, the first is one-fourth of the sum of the last three. The first number is –

A. 15 B. 42 C. 45 D. 48 Answer: Option D

### Solution(By Apex Team)

Let the four numbers be a, b, c and d respectively Then, $\begin{array}{l}\text{⇒ a =}\frac{1}{4}\text{(b + c + d)}\\ \text{⇒ b + c + d = 4a}\\ \text{Also,}\\ \text{a + b + c + d = 60 × 4 = 240}\\ \text{⇒ a + 4a = 240}\\ \text{⇒ 5a = 240}\\ \text{⇒ a = 48}\\ \text{Hence, first number = 48}\end{array}$

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