Will's current age is 7 times as old as Peter's age years ago. Today, Peter's age is Will's age the same number of years ago. How old is Peter's age now if the total of their current age is 66?
| |
Will |
Peter |
Difference |
Total |
| Before |
1 p |
1 u |
1 p - 1 u |
|
| Change |
+ ? |
+ ? |
|
|
| After |
7 u |
1 p |
7 u - 1 p |
66 |
Total age of Will and Peter today = 7 u + 1 p
7 u + 1 p = 66 --- (1)
The difference in Will's age and Peter's age remains the same.
7 u - 1 p = 1 p - 1 u
7 u + 1 u = 1 p + 1 p
8 u = 2 p
4 u = 1 p
Substitute 1 p = 4 u into (1).
7 u + 1 p = 66
7 u + 4 u = 66
11 u = 66
1 u = 66 ÷ 11 = 6
Will's age now
= 66 - 7 u
= 66 - 7 x 6
= 66 - 42
= 24
Answer(s): 24
