Four years ago, the ratio of the age of A and B was 3 : 4. The average of the present age of A, B and C is 26 years. C is 11 years younger than B. What is the present age of B?

Explanation

Ratio of age of A and B four years ago was 3 : 4. Let the age of A and B four years ago be 3x and 4x respectively. Therefore, present age of A = 3x + 4; present age of B = 4x + 4. C is 11 years younger than B. Present age of C = 4x + 4 - 11 = 4x - 7. Average age of A, B and C is 26 years. Therefore, sum of ages of A, B and C = 26 x 3 = 78 => (3x + 4) + (4x + 4) + (4x - 7) = 78 => 11x + 1 = 78 => x = 7. Present age of B = 4x + 4 = (4 x 7) + 4 = 32. Therefore, the present age of B is 32 years.