Paul's current age is 5 times as old as Luis's age years ago. Today, Luis's age is Paul's age the same number of years ago. How old is Luis's age now if the total of their current age is 24?
| |
Paul |
Luis |
Difference |
Total |
| Before |
1 p |
1 u |
1 p - 1 u |
|
| Change |
+ ? |
+ ? |
|
|
| After |
5 u |
1 p |
5 u - 1 p |
24 |
Total age of Paul and Luis today = 5 u + 1 p
5 u + 1 p = 24 --- (1)
The difference in Paul's age and Luis's age remains the same.
5 u - 1 p = 1 p - 1 u
5 u + 1 u = 1 p + 1 p
6 u = 2 p
3 u = 1 p
Substitute 1 p = 3 u into (1).
5 u + 1 p = 24
5 u + 3 u = 24
8 u = 24
1 u = 24 ÷ 8 = 3
Paul's age now
= 24 - 5 u
= 24 - 5 x 3
= 24 - 15
= 9
Answer(s): 9
