Oscar is 3 times as old as his brother. In 20 years' time, Oscar will be 16 years less than twice of his brother's age. How old will Oscar be in 5 years' time?
|
Oscar |
Oscar's brother |
Difference |
Before |
3 u |
1 u |
2 u |
Change |
+ 20 |
+ 20 |
|
After |
2 p - 16 |
1 p |
1 p - 16 |
Difference in their ages at first
= 3 u - 1 u
= 2 u
Difference in their ages in the end
= 2 p - 16 - 1 p
= 1 p - 16
The difference in their ages remains unchanged.
2 u = 1 p - 16
2 u + 16 =
1 p --- (1)
Age of Oscar's brother in 20 years' time
= 1 u + 20
1 u + 20 =
1 p --- (2)
(1) = (2)
2 u + 16 = 1 u + 20
2 u - 1 u = 20 - 16
1 u = 4
Oscar's current age
= 3 u
= 3 x 4
= 12
Oscar's age in 5 years' time
= 12 + 5
= 17
Answer(s): 17