When Anna was 41 years old, her son was 2 times her daughter's age. Anna would be twice her son's age when her daughter was 32 years old. How old would Anna be when her daughter was 12 years old?
|
Anna |
Son |
Daughter |
Before |
41 |
2 u |
1 u |
Change |
+ ? |
+ ? |
+ ? |
After |
2 p |
1 p |
32 |
The difference in the ages between Anna and her son remains unchanged.
Difference in Anna's and her son's ages at first
41 - 2 u = 2 p - 1 p
41 - 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 - 32
1 u + 32 =
1 p --- (2)
Make p the same.
(1) = (2)
41 - 2 u = 1 u + 32
1 u + 2 u = 41 - 32
3 u = 9
1 u = 9 ÷ 3 = 3
Age difference between Anna and her daughter
= 41 - 1 u
= 41 - 3
= 38
Anna's age when her daughter was 12 years old
= 38 + 12
= 50
Answer(s): 50