Ten years ago, A was half of B in age. If the ratio of their present age is 3 : 4. What will be the total of their present ages?

Question: Ten years ago. A was half of B in age. If the ratio of their present age is 3 : 4. What will be the total of their present ages?

Solution:
let, Ten years ago, A was x years old
B was 2x years old

ATQ,
(x + 10)/(2x + 10) = 3/4
⇒ 4x + 40 = 6x = 30
⇒ 6x - 4x = 40 - 30
⇒ 2x = 10
∴ x = 5

total present age = x + 2x + 20
= 3x + 20
= 3 × 5 + 20
= 35 years