Fabian's age is
25 of his grandmother's. His grandmother will be 60 years old in 10 years' time. In how many years' time will Fabian's age be
12 that of his grandmother's?
| |
Fabian |
His grandmother |
Difference |
| Before |
2x1 =
2 u |
5x1 =
5 u |
3x1 =
3 u |
| Change 1 |
+ 10 |
+ 10 |
|
| After |
|
60 |
|
| Change 2 |
+ ? |
+ ? |
|
| After 2 |
1x3 =
3 u |
2x3 =
6 u |
1x3 =
3 u |
The age difference between Fabian and his grandmother remains unchanged.
LCM of 3 and 1 is 3.
5 u + 10 = 60
5 u = 60 - 10
5 u = 50
1 u = 50 ÷ 5 = 10
Number of years' time when Fabian's age will be
12 that of his grandmother's age
= 3 u - 2 u
= 1 u
= 1 x 10
= 10
Answer(s): 10
