Oscar is 3 times as old as his brother. In 17 years' time, Oscar will be 11 years less than twice of his brother's age. How old will Oscar be in 7 years' time?
|
Oscar |
Oscar's brother |
Difference |
Before |
3 u |
1 u |
2 u |
Change |
+ 17 |
+ 17 |
|
After |
2 p - 11 |
1 p |
1 p - 11 |
Difference in their ages at first
= 3 u - 1 u
= 2 u
Difference in their ages in the end
= 2 p - 11 - 1 p
= 1 p - 11
The difference in their ages remains unchanged.
2 u = 1 p - 11
2 u + 11 =
1 p --- (1)
Age of Oscar's brother in 17 years' time
= 1 u + 17
1 u + 17 =
1 p --- (2)
(1) = (2)
2 u + 11 = 1 u + 17
2 u - 1 u = 17 - 11
1 u = 6
Oscar's current age
= 3 u
= 3 x 6
= 18
Oscar's age in 7 years' time
= 18 + 7
= 25
Answer(s): 25