Oliver's age is
25 his sister's age now. In 20 years' time, his age will be
23 that of his sister's. How old is Oliver now?
| |
Oliver |
Oliver's sister |
Difference |
| Before |
2x1 =
2 u |
5x1 =
5 u |
3x1 =
3 u |
| Change |
+ 20 |
+ 20 |
|
| After |
2x3 =
6 u |
3x3 =
9 u |
1x3 =
3 u |
The difference in the age between Oliver and Oliver's sister remains unchanged. Make the difference in age the same. LCM of 3 and 1 is 3.
Increase in the age of Oliver
= 6 u - 2 u
= 4 u
4 u = 20
1 u = 20 ÷ 4 = 5
Oliver's age now
= 2 u
= 2 x 5
= 10
Answer(s): 10
