When Jean was 26 years old, her son was 2 times her daughter's age. Jean would be twice her son's age when her daughter was 20 years old. How old would Jean be when her daughter was 16 years old?

	Jean	Son	Daughter
Before	26	2 u	1 u
Change	+ ?	+ ?	+ ?
After	2 p	1 p	20

The difference in the ages between Jean and her son remains unchanged.

Difference in Jean's and her son's ages at first
26 - 2 u = 2 p - 1 p
26 - 2 u = 1 p --- (1)

The difference in the ages between her son and her daughter remains unchanged.

Difference in her son's and her daughter's ages at first
2 u - 1 u = 1 p - 20
1 u + 20 = 1 p --- (2)

Make p the same.

(1) = (2)
26 - 2 u = 1 u + 20
1 u + 2 u = 26 - 20
3 u = 6

1 u = 6 ÷ 3 = 2

Age difference between Jean and her daughter
= 26 - 1 u
= 26 - 2
= 24

Jean's age when her daughter was 16 years old
= 24 + 16
= 40

Answer(s): 40