The ratio of the present ages of P and Q is 3 : 4. Five years ago, the ratio of their ages was 5 : 7. Find their present ages.

As the ratio of their present ages is 3: 4, let their present ages be 3x and 4x. So, 5 years ago, as the ratio of their ages was 5 : 7, =>(3x-5) : (4x-5) = 5 : 7. Solving, we get X = 10. Hence, their present ages are 3x = 30 and 4x = 40