Ruth is five years older than Tom. Two years from now, Tom will be 5 years old. Find the sum of their ages three years from now.

Let's first find the current age of Tom. If two years from now Tom will be 5 years old, then his current age is 5 years - 2 years = 3 years old.
Since Ruth is five years older than Tom, her current age is 3 years + 5 years = 8 years old.
To find the sum of their ages three years from now, we will add 3 years to their current ages:
Tom's age three years from now: 3 years + 3 years = 6 years old.
Ruth's age three years from now: 8 years + 3 years = 11 years old.
The sum of their ages three years from now is 6 years + 11 years = 17 years.