I am 48 and my wife is 39. How old was I when I was twice her age? How old was I when I was four times as old as her?

Question

A husband and wife have a combined age of 91. If husband is now twice as old as his wife was when he was as old as she is now.
How old are they now?

Answer 1

[48 - x] = 2 x [39 - x]
2x - x = (39 x 2) - 48
x = 30

ie., when the husband was 48 - 30 = 18 the wife was 39 - 30 = 9 years old ie., husband: wife:: 2: 1.
similarly

[48 - x] = 4 x [39 - x]
4x - x = (39 x 4) - 48
3x = 108
x = 36.

ie., when the husband was 48 - 36 = 12 the wife was 39 - 36 = 3 years old ie., husband: wife:: 4: 1.