Xylia will be 70 years old in 18 years' time. Now, Xandra's age is 34 of Xylia's age. What was Xandra's age when she was 9 years less than 90% of Xylia's age?
| |
Xandra |
Xylia |
Difference |
| Before |
9 p - 9 |
10 p |
1 p + 9 |
| Change 1 |
+ ? |
+ ? |
|
| After 1 (Now) |
3 u |
4 u |
1 u |
| Change 2 |
+ 18 |
+ 18 |
|
| After |
3 u + 18 |
70 |
|
Xylia's age in 18 years' time = 4 u + 18
4 u + 18 = 70
4 u = 70 - 18
4 u = 52
1 u = 52 ÷ 4 = 13
Difference between Xylia's age and Xandra's age
= 1 u
= 13
90% =
90100 =
910 Difference in Xylia's age and Xandra's age at first
= 10 p - (9 p - 9)
= 1 p + 9
The difference in age between Xylia and Xandra remains unchanged.
1 p + 9 = 13
1 p = 13 - 9 = 4
Xandra's age when she was 9 years less than 90% of Xylia's age
= 9 p - 9
= 9 x 4 - 9
= 36 - 9
= 27
Answer(s): 27
