Seth's age is
13 of his grandaunt's. His grandaunt will be 47 years old in 5 years' time. In how many years' time will Seth's age be
12 that of his grandaunt's?
| |
Seth |
His grandaunt |
Difference |
| Before |
1x1 =
1 u |
3x1 =
3 u |
2x1 =
2 u |
| Change 1 |
+ 5 |
+ 5 |
|
| After |
|
47 |
|
| Change 2 |
+ ? |
+ ? |
|
| After 2 |
1x2 =
2 u |
2x2 =
4 u |
1x2 =
2 u |
The age difference between Seth and his grandaunt remains unchanged.
LCM of 2 and 1 is 2.
3 u + 5 = 47
3 u = 47 - 5
3 u = 42
1 u = 42 ÷ 3 = 14
Number of years' time when Seth's age will be
12 that of his grandaunt's age
= 2 u - 1 u
= 1 u
= 1 x 14
= 14
Answer(s): 14
