Warren's age is
15 of his grandfather's. His grandfather will be 71 years old in 16 years' time. In how many years' time will Warren's age be
12 that of his grandfather's?
| |
Warren |
His grandfather |
Difference |
| Before |
1x1 =
1 u |
5x1 =
5 u |
4x1 =
4 u |
| Change 1 |
+ 16 |
+ 16 |
|
| After |
|
71 |
|
| Change 2 |
+ ? |
+ ? |
|
| After 2 |
1x4 =
4 u |
2x4 =
8 u |
1x4 =
4 u |
The age difference between Warren and his grandfather remains unchanged.
LCM of 4 and 1 is 4.
5 u + 16 = 71
5 u = 71 - 16
5 u = 55
1 u = 55 ÷ 5 = 11
Number of years' time when Warren's age will be
12 that of his grandfather's age
= 4 u - 1 u
= 3 u
= 3 x 11
= 33
Answer(s): 33
