Gabriel's age is
37 of his grandmother's. His grandmother will be 89 years old in 12 years' time. In how many years' time will Gabriel's age be
12 that of his grandmother's?
| |
Gabriel |
His grandmother |
Difference |
| Before |
3x1 =
3 u |
7x1 =
7 u |
4x1 =
4 u |
| Change 1 |
+ 12 |
+ 12 |
|
| After |
|
89 |
|
| Change 2 |
+ ? |
+ ? |
|
| After 2 |
1x4 =
4 u |
2x4 =
8 u |
1x4 =
4 u |
The age difference between Gabriel and his grandmother remains unchanged.
LCM of 4 and 1 is 4.
7 u + 12 = 89
7 u = 89 - 12
7 u = 77
1 u = 77 ÷ 7 = 11
Number of years' time when Gabriel's age will be
12 that of his grandmother's age
= 4 u - 3 u
= 1 u
= 1 x 11
= 11
Answer(s): 11
