When Lynn was 39 years old, her son was 2 times her daughter's age. Lynn would be twice her son's age when her daughter was 24 years old. How old would Lynn be when her daughter was 4 years old?

	Lynn	Son	Daughter
Before	39	2 u	1 u
Change	+ ?	+ ?	+ ?
After	2 p	1 p	24

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

Difference in Lynn's and her son's ages at first
39 - 2 u = 2 p - 1 p
39 - 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 - 24
1 u + 24 = 1 p --- (2)

Make p the same.

(1) = (2)
39 - 2 u = 1 u + 24
1 u + 2 u = 39 - 24
3 u = 15

1 u = 15 ÷ 3 = 5

Age difference between Lynn and her daughter
= 39 - 1 u
= 39 - 5
= 34

Lynn's age when her daughter was 4 years old
= 34 + 4
= 38

Answer(s): 38