Xuan will be 55 years old in 20 years' time. Now, Fanny's age is 45 of Xuan's age. What was Fanny's age when she was 3 years less than 80% of Xuan's age?
| |
Fanny |
Xuan |
Difference |
| Before |
4 p - 3 |
5 p |
1 p + 3 |
| Change 1 |
+ ? |
+ ? |
|
| After 1 (Now) |
4 u |
5 u |
1 u |
| Change 2 |
+ 20 |
+ 20 |
|
| After |
4 u + 20 |
55 |
|
Xuan's age in 20 years' time = 5 u + 20
5 u + 20 = 55
5 u = 55 - 20
5 u = 35
1 u = 35 ÷ 5 = 7
Difference between Xuan's age and Fanny's age
= 1 u
= 7
80% =
80100 =
45 Difference in Xuan's age and Fanny's age at first
= 5 p - (4 p - 3)
= 1 p + 3
The difference in age between Xuan and Fanny remains unchanged.
1 p + 3 = 7
1 p = 7 - 3 = 4
Fanny's age when she was 3 years less than 80% of Xuan's age
= 4 p - 3
= 4 x 4 - 3
= 16 - 3
= 13
Answer(s): 13
