Paul's age is
27 of his grandaunt's. His grandaunt will be 68 years old in 12 years' time. In how many years' time will Paul's age be
12 that of his grandaunt's?
|
Paul |
His grandaunt |
Difference |
Before |
2x1 = 2 u |
7x1 = 7 u |
5x1 = 5 u |
Change 1 |
+ 12 |
+ 12 |
|
After |
|
68 |
|
Change 2 |
+ ? |
+ ? |
|
After 2 |
1x5 = 5 u |
2x5 = 10 u |
1x5 = 5 u |
The age difference between Paul and his grandaunt remains unchanged.
LCM of 5 and 1 is 5.
7 u + 12 = 68
7 u = 68 - 12
7 u = 56
1 u = 56 ÷ 7 = 8
Number of years' time when Paul's age will be
12 that of his grandaunt's age
= 5 u - 2 u
= 3 u
= 3 x 8
= 24
Answer(s): 24