Eric's age is
15 of his granduncle's. His granduncle will be 58 years old in 18 years' time. In how many years' time will Eric's age be
12 that of his granduncle's?
| |
Eric |
His granduncle |
Difference |
| Before |
1x1 =
1 u |
5x1 =
5 u |
4x1 =
4 u |
| Change 1 |
+ 18 |
+ 18 |
|
| After |
|
58 |
|
| Change 2 |
+ ? |
+ ? |
|
| After 2 |
1x4 =
4 u |
2x4 =
8 u |
1x4 =
4 u |
The age difference between Eric and his granduncle remains unchanged.
LCM of 4 and 1 is 4.
5 u + 18 = 58
5 u = 58 - 18
5 u = 40
1 u = 40 ÷ 5 = 8
Number of years' time when Eric's age will be
12 that of his granduncle's age
= 4 u - 1 u
= 3 u
= 3 x 8
= 24
Answer(s): 24
