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