The ratio between the present ages of A and B is 5 : 3 respectively. The ratio between A’s age 4 years ago and B’s age 4 years hence is 1 : 1. What is the ratio between A’s age 4 years hence and B’s age 4 years ago ?

\par Let the present ages of A and B be 5x and 3x years respectively.

\frac{5x - 4}{3x + 4} = \frac{1}{1}

5x - 4 = 3x + 4

2x = 8

x = 4

\par Required ratio = (5x + 4) : (3x - 4) = 24 : 8 = 3 : 1