Harry's mother is 4 times as old as him. His mother will be 27 years old in 3 years' time. In how many years' time will Harry's age be 60% that of his mother's?
| |
Harry's mother |
Harry |
Difference |
Before
(now) |
4x2 =
8 u |
1x2 =
2 u |
3x2 =
6 u |
| Change 1 |
+ 3 |
+ 3 |
|
| After 1 |
27 |
|
|
| Change 2 |
+ ? |
+ ? |
|
| After 2 |
5x3 =
15 u |
3x3 =
9 u |
2x3 =
6 u |
60% =
60100 =
35 Harry's mother : Harry = 5 : 3
The difference in age between Harry's mother and Harry always remains the same. Make the difference in age between Harry's mother and Harry the same. LCM of 3 and 2 is 6.
8 u + 3 = 27
8 u = 27 - 3
8 u = 24
1 u = 24 ÷ 8 = 3
Number of years' time when Harry's age will be 60% that of his mother's
= 15 u - 27
= 15 x 3 - 27
= 45 - 27
= 18
Answer(s): 18
