Question 93340
Let M = mother's age and S = sister's age.
From the problem description, you can write:
M = 3S  Mother's age is three times sister's age.
M-S = 22 The difference in their ages is 22. In this equation, substitute M = 3S.
3S-S = 22
2S = 22
S = 11
M = 3(11)
M = 33

Mother's age is 33 years.
Sister's age is 11 years.