Sabrina's father is 6 times as old as her. Sabrina will be 13 years old in 9 years' time. In how many years' time will Sabrina's age be 60% that of her father's?
| |
Sabrina's father |
Sabrina |
Difference |
Before
(now) |
6x2 =
12 u |
1x2 =
2 u |
5x2 =
10 u |
| Change 1 |
+ 9 |
+ 9 |
|
| After 1 |
|
13 |
|
| Change 2 |
+ ? |
+ ? |
|
| After 2 |
5x5 =
25 u |
3x5 =
15 u |
2x5 =
10 u |
60% =
60100 =
35 Sabrina's father : Sabrina = 5 : 3
The difference in age between Sabrina's father and Sabrina always remains the same. Make the difference in age between Sabrina's father and Sabrina the same. LCM of 5 and 2 is 10.
2 u + 9 = 13
2 u = 13 - 9
2 u = 4
1 u = 4 ÷ 2 = 2
Number of years' time when Sabrina's age will be 60% that of her father's
= 25 u - 33
= 25 x 2 - 33
= 50 - 33
= 17
Answer(s): 17
