Question

The present ages of 3 brothers are in the proportion 3 : 4 : 5. After 10 years the sum of their ages will be 78. What are their ages now?

• A. 12, 16 and 20
• B. 15, 20 and 25
• C. 21, 28 and 35
• D. 24, 32 and 40

Answer 1

The correct option is A 12, 16 and 20

Let 3x, 4x, 5x, be the present age of 3 brothers.

After 10 years, their ages will be 3x + 10 , 4x +10, 5x +10

3x +10 +4x +10 + 5x + 10 = 78
12x + 30 = 78
x = 4

Hence the present age of three brothers is 12, 16 and 20 years.

Alternate Solution:

Can be directly solved using the given options since the sum of their present age = 78 - 30 = 48

Which is satisfied by option 'A' alone.