When Lynn was 40 years old, her daughter was 2 times her son's age. Lynn would be twice her daughter's age when her son was 22 years old. How old would Lynn be when her son was 10 years old?

	Lynn	Daughter	Son
Before	40	2 u	1 u
Change	+ ?	+ ?	+ ?
After	2 p	1 p	22

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

Difference in Lynn's and her daughter's ages at first
40 - 2 u = 2 p - 1 p
40 - 2 u = 1 p --- (1)

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

Difference in her daughter's and her son's ages at first
2 u - 1 u = 1 p - 22
1 u + 22 = 1 p --- (2)

Make p the same.

(1) = (2)
40 - 2 u = 1 u + 22
1 u + 2 u = 40 - 22
3 u = 18

1 u = 18 ÷ 3 = 6

Age difference between Lynn and her son
= 40 - 1 u
= 40 - 6
= 34

Lynn's age when her son was 10 years old
= 34 + 10
= 44

Answer(s): 44