Oliver's age is
25 of his grandmother's. His grandmother will be 83 years old in 13 years' time. In how many years' time will Oliver's age be
12 that of his grandmother's?
| |
Oliver |
His grandmother |
Difference |
| Before |
2x1 =
2 u |
5x1 =
5 u |
3x1 =
3 u |
| Change 1 |
+ 13 |
+ 13 |
|
| After |
|
83 |
|
| Change 2 |
+ ? |
+ ? |
|
| After 2 |
1x3 =
3 u |
2x3 =
6 u |
1x3 =
3 u |
The age difference between Oliver and his grandmother remains unchanged.
LCM of 3 and 1 is 3.
5 u + 13 = 83
5 u = 83 - 13
5 u = 70
1 u = 70 ÷ 5 = 14
Number of years' time when Oliver's age will be
12 that of his grandmother's age
= 3 u - 2 u
= 1 u
= 1 x 14
= 14
Answer(s): 14
