Charlie's age is
17 of his grandaunt's. His grandaunt will be 66 years old in 10 years' time. In how many years' time will Charlie's age be
12 that of his grandaunt's?
|
Charlie |
His grandaunt |
Difference |
Before |
1x1 = 1 u |
7x1 = 7 u |
6x1 = 6 u |
Change 1 |
+ 10 |
+ 10 |
|
After |
|
66 |
|
Change 2 |
+ ? |
+ ? |
|
After 2 |
1x6 = 6 u |
2x6 = 12 u |
1x6 = 6 u |
The age difference between Charlie and his grandaunt remains unchanged.
LCM of 6 and 1 is 6.
7 u + 10 = 66
7 u = 66 - 10
7 u = 56
1 u = 56 ÷ 7 = 8
Number of years' time when Charlie's age will be
12 that of his grandaunt's age
= 6 u - 1 u
= 5 u
= 5 x 8
= 40
Answer(s): 40