Henry's age is
15 of his granduncle's. His granduncle will be 68 years old in 8 years' time. In how many years' time will Henry's age be
12 that of his granduncle's?
| |
Henry |
His granduncle |
Difference |
| Before |
1x1 =
1 u |
5x1 =
5 u |
4x1 =
4 u |
| Change 1 |
+ 8 |
+ 8 |
|
| After |
|
68 |
|
| Change 2 |
+ ? |
+ ? |
|
| After 2 |
1x4 =
4 u |
2x4 =
8 u |
1x4 =
4 u |
The age difference between Henry and his granduncle remains unchanged.
LCM of 4 and 1 is 4.
5 u + 8 = 68
5 u = 68 - 8
5 u = 60
1 u = 60 ÷ 5 = 12
Number of years' time when Henry's age will be
12 that of his granduncle's age
= 4 u - 1 u
= 3 u
= 3 x 12
= 36
Answer(s): 36
