Xavier's age is
14 of his grandmother's. His grandmother will be 63 years old in 7 years' time. In how many years' time will Xavier's age be
12 that of his grandmother's?
| |
Xavier |
His grandmother |
Difference |
| Before |
1x1 =
1 u |
4x1 =
4 u |
3x1 =
3 u |
| Change 1 |
+ 7 |
+ 7 |
|
| After |
|
63 |
|
| Change 2 |
+ ? |
+ ? |
|
| After 2 |
1x3 =
3 u |
2x3 =
6 u |
1x3 =
3 u |
The age difference between Xavier and his grandmother remains unchanged.
LCM of 3 and 1 is 3.
4 u + 7 = 63
4 u = 63 - 7
4 u = 56
1 u = 56 ÷ 4 = 14
Number of years' time when Xavier's age will be
12 that of his grandmother's age
= 3 u - 1 u
= 2 u
= 2 x 14
= 28
Answer(s): 28
