Rael's age is
25 of his grandaunt's. His grandaunt will be 65 years old in 15 years' time. In how many years' time will Rael's age be
23 that of his grandaunt's?
| |
Rael |
His grandaunt |
Difference |
| Before |
2x1 =
2 u |
5x1 =
5 u |
3x1 =
3 u |
| Change 1 |
+ 15 |
+ 15 |
|
| After |
|
65 |
|
| Change 2 |
+ ? |
+ ? |
|
| After 2 |
2x3 =
6 u |
3x3 =
9 u |
1x3 =
3 u |
The age difference between Rael and his grandaunt remains unchanged.
LCM of 3 and 1 is 3.
5 u + 15 = 65
5 u = 65 - 15
5 u = 50
1 u = 50 ÷ 5 = 10
Number of years' time when Rael's age will be
23 that of his grandaunt's age
= 6 u - 2 u
= 4 u
= 4 x 10
= 40
Answer(s): 40
