Will's auntie is 5 times as old as him. His auntie will be 40 years old in 5 years' time. In how many years' time will Will's age be 60% that of his auntie's?
| |
Will's auntie |
Will |
Difference |
Before
(now) |
5x1 =
5 u |
1x1 =
1 u |
4x1 =
4 u |
| Change 1 |
+ 5 |
+ 5 |
|
| After 1 |
40 |
|
|
| Change 2 |
+ ? |
+ ? |
|
| After 2 |
5x2 =
10 u |
3x2 =
6 u |
2x2 =
4 u |
60% =
60100 =
35 Will's auntie : Will = 5 : 3
The difference in age between Will's auntie and Will always remains the same. Make the difference in age between Will's auntie and Will the same. LCM of 4 and 2 is 4.
5 u + 5 = 40
5 u = 40 - 5
5 u = 35
1 u = 35 ÷ 5 = 7
Number of years' time when Will's age will be 60% that of his auntie's
= 10 u - 40
= 10 x 7 - 40
= 70 - 40
= 30
Answer(s): 30
