A grandparent is 71 and a grandchild is 27 today. How old was the grandchild when the grandparent was 50?

Question: A grandparent is 71 and a grandchild is 27 today. How old was the grandchild when the grandparent was 50?

1. 7 years
2. 6 years
3. 5 years
4. 8 years

Correct Answer: B — 6 years

Explanation: Ages change by the same number of years; subtract the years needed for the elder to reach 50.
Grandchild then = 27 − (71 − 50) = 6 years.