Gabby's auntie is 4 times as old as her. Gabby will be 20 years old in 12 years' time. In how many years' time will Gabby's age be 60% that of her auntie's?
| |
Gabby's auntie |
Gabby |
Difference |
Before
(now) |
4x2 =
8 u |
1x2 =
2 u |
3x2 =
6 u |
| Change 1 |
+ 12 |
+ 12 |
|
| After 1 |
|
20 |
|
| Change 2 |
+ ? |
+ ? |
|
| After 2 |
5x3 =
15 u |
3x3 =
9 u |
2x3 =
6 u |
60% =
60100 =
35 Gabby's auntie : Gabby = 5 : 3
The difference in age between Gabby's auntie and Gabby always remains the same. Make the difference in age between Gabby's auntie and Gabby the same. LCM of 3 and 2 is 6.
2 u + 12 = 20
2 u = 20 - 12
2 u = 8
1 u = 8 ÷ 2 = 4
Number of years' time when Gabby's age will be 60% that of her auntie's
= 15 u - 44
= 15 x 4 - 44
= 60 - 44
= 16
Answer(s): 16
