Answer: 39 years old
Explanation:
First find Sarah's age.
It is said that their ages sum up to 50 and that Sarah's mother is 28 years older than Sarah.
Assume Sarah's age is x.
Sarah's mother's age would be: x + 28.
The expression would therefore be:
x + (x + 28) = 50
2x + 28 = 50
2x = 50 - 28
x = 22/2
x = 11
Sarah is 11 which means her mom is:
= 11 + 28
= 39 years old