A husband and a wife have a combined age of 91. The husband is now twice as old as his wife was when he was as old as she is now. How old are they?
Answer
Husband = 52, Wife = 39.
If we call the husband’s age h, and the wife’s w, we know:
h + w = 91 (a)
Their age difference is h – w. We know the husband is 2 * (how old his wife was when he was her age), so we need to take their age difference
off his current wife’s age, as follows:
2 * (w – (h – w)) = h
Simplifying this we get:
4w = 3h
Plugging this back into (a) gives the required answer.