Glen's age is
25 of his grandfather's. His grandfather will be 73 years old in 18 years' time. In how many years' time will Glen's age be
23 that of his grandfather's?
| |
Glen |
His grandfather |
Difference |
| Before |
2x1 =
2 u |
5x1 =
5 u |
3x1 =
3 u |
| Change 1 |
+ 18 |
+ 18 |
|
| After |
|
73 |
|
| Change 2 |
+ ? |
+ ? |
|
| After 2 |
2x3 =
6 u |
3x3 =
9 u |
1x3 =
3 u |
The age difference between Glen and his grandfather remains unchanged.
LCM of 3 and 1 is 3.
5 u + 18 = 73
5 u = 73 - 18
5 u = 55
1 u = 55 ÷ 5 = 11
Number of years' time when Glen's age will be
23 that of his grandfather's age
= 6 u - 2 u
= 4 u
= 4 x 11
= 44
Answer(s): 44
