The sum of ages of A and B is 40 years. 5 years ago, A was twice as old as B. Find B’s present age.

Question

The sum of ages of A and B is 40 years. 5 years ago, A was twice as old as B. Find B&#8217;s present age.

Accepted Answer

15 years. Let A = present age of A, B = present age of B .  A + B = 40 .  (A-5) = 2(B-5) => A = 2B - 5 .  Substituting: 2B - 5 + B = 40 => 3B = 45 => B = 15

The sum of ages of A and B is 40 years. 5 years ago, A was twice as old as B. Find B’s present age.

Explanation