Sam's age is
37 of his grandaunt's. His grandaunt will be 85 years old in 8 years' time. In how many years' time will Sam's age be
12 that of his grandaunt's?
| |
Sam |
His grandaunt |
Difference |
| Before |
3x1 =
3 u |
7x1 =
7 u |
4x1 =
4 u |
| Change 1 |
+ 8 |
+ 8 |
|
| After |
|
85 |
|
| Change 2 |
+ ? |
+ ? |
|
| After 2 |
1x4 =
4 u |
2x4 =
8 u |
1x4 =
4 u |
The age difference between Sam and his grandaunt remains unchanged.
LCM of 4 and 1 is 4.
7 u + 8 = 85
7 u = 85 - 8
7 u = 77
1 u = 77 ÷ 7 = 11
Number of years' time when Sam's age will be
12 that of his grandaunt's age
= 4 u - 3 u
= 1 u
= 1 x 11
= 11
Answer(s): 11
