Age: 5 years ago, the ratio of the ages of A and B was 5:3. The sum of their present ages is 50 years. Find A’s present age.

Let A's current age be a, and B's be b. Five years ago, their ages were a–5 and b–5, and the ratio was 5:3. So: (a–5)/(b–5) = 5/3 → cross-multiplies to 3a – 5b = –10. Also, a + b = 50 → a = 50 – b.

Substitute into the first equation: 3(50 – b) – 5b = –10 → 150 – 3b – 5b = –10 → 150 – 8b = –10 → 8b = 160 → b = 20 Then a = 50 – 20 = 30

A’s present age is 30 years.