Xandra's father is 4 times as old as her. Xandra will be 22 years old in 12 years' time. In how many years' time will Xandra's age be 60% that of her father's?
| |
Xandra's father |
Xandra |
Difference |
Before
(now) |
4x2 =
8 u |
1x2 =
2 u |
3x2 =
6 u |
| Change 1 |
+ 12 |
+ 12 |
|
| After 1 |
|
22 |
|
| Change 2 |
+ ? |
+ ? |
|
| After 2 |
5x3 =
15 u |
3x3 =
9 u |
2x3 =
6 u |
60% =
60100 =
35 Xandra's father : Xandra = 5 : 3
The difference in age between Xandra's father and Xandra always remains the same. Make the difference in age between Xandra's father and Xandra the same. LCM of 3 and 2 is 6.
2 u + 12 = 22
2 u = 22 - 12
2 u = 10
1 u = 10 ÷ 2 = 5
Number of years' time when Xandra's age will be 60% that of her father's
= 15 u - 52
= 15 x 5 - 52
= 75 - 52
= 23
Answer(s): 23
