Given: Ratio of Present age of A and B = 5 : 3 The difference between the age of A 10 years hence and the age of B 4 years ago = 20 years Calculation: Let the Present age of A and B be 5x and 3x respectively ⇒ The age of A 10 years hence = 5x + 10 ⇒ The age of B 4 years ago = 3x - 4 Now, the difference: (5x + 10) - (3x - 4) = 20 ⇒ 2x + 14 = 20 ⇒ 2x = 6 ⇒ x = 3 ∴ The present age of A = 5x = 5 × 3 = 15 years