Eric's current age is 3 times as old as Carl's age years ago. Today, Carl's age is Eric's age the same number of years ago. How old is Eric's age now if the total of their current age is 40?
| |
Eric |
Carl |
Difference |
Total |
| Before |
1 p |
1 u |
1 p - 1 u |
|
| Change |
+ ? |
+ ? |
|
|
| After |
3 u |
1 p |
3 u - 1 p |
40 |
Total age of Eric and Carl today = 3 u + 1 p
3 u + 1 p = 40 --- (1)
The difference in Eric's age and Carl's age remains the same.
3 u - 1 p = 1 p - 1 u
3 u + 1 u = 1 p + 1 p
4 u = 2 p
2 u = 1 p
Substitute 1 p = 2 u into (1).
3 u + 1 p = 40
3 u + 2 u = 40
5 u = 40
1 u = 40 ÷ 5 = 8
Eric's age now
= 3 u
= 3 x 8
= 24
Answer(s): 24
