Question

Robert is 15 years older than his sister, Helen. The sum of their ages is 63. Find their ages.

Answer 1

Helen is 24; Robert is 39

Explanation:

If Helen's age is x, Robert's age is x + 15. We can write:

x + x + 15 = 63

2x + 15 = 63

2x = 48

x = 24

This means that Helen's age is 24 and Robert's age is 24 + 15 = 39.