George's age is
37 of his grandmother's. His grandmother will be 63 years old in 7 years' time. In how many years' time will George's age be
23 that of his grandmother's?
| |
George |
His grandmother |
Difference |
| Before |
3x1 =
3 u |
7x1 =
7 u |
4x1 =
4 u |
| Change 1 |
+ 7 |
+ 7 |
|
| After |
|
63 |
|
| Change 2 |
+ ? |
+ ? |
|
| After 2 |
2x4 =
8 u |
3x4 =
12 u |
1x4 =
4 u |
The age difference between George and his grandmother remains unchanged.
LCM of 4 and 1 is 4.
7 u + 7 = 63
7 u = 63 - 7
7 u = 56
1 u = 56 ÷ 7 = 8
Number of years' time when George's age will be
23 that of his grandmother's age
= 8 u - 3 u
= 5 u
= 5 x 8
= 40
Answer(s): 40
