One year ago, the age of B was twice that of A. After 9 years, if the ratio of the ages of B and A would be 4 ∶ 3, then the sum of their present ages is _____ years.
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 17.
One year ago, the age of B was twice that of A.
Let the age of A and B one year ago be x and 2x respectively.
So, (2x + 1 + 9)/(x + 1 + 9) = 4/3
⇒ (2x + 10) / (x + 10) = 4/3
⇒ 6x + 30 = 4x + 40
⇒ 2x = 10
⇒ x = 10/2 = 5
So, the present age of A = x + 1 = 5 + 1 = 6 years
The present age of B = 2x + 1 = 10 + 1 = 11 years
Sum of their age = 6 + 11 = 17 years
Therefore, the sum of the present age of A and B is 17 years.