Daniel's current age is 9 times as old as Perry's age years ago. Today, Perry's age is Daniel's age the same number of years ago. How old is Daniel's age now if the total of their current age is 56?
| |
Daniel |
Perry |
Difference |
Total |
| Before |
1 p |
1 u |
1 p - 1 u |
|
| Change |
+ ? |
+ ? |
|
|
| After |
9 u |
1 p |
9 u - 1 p |
56 |
Total age of Daniel and Perry today = 9 u + 1 p
9 u + 1 p = 56 --- (1)
The difference in Daniel's age and Perry's age remains the same.
9 u - 1 p = 1 p - 1 u
9 u + 1 u = 1 p + 1 p
10 u = 2 p
5 u = 1 p
Substitute 1 p = 5 u into (1).
9 u + 1 p = 56
9 u + 5 u = 56
14 u = 56
1 u = 56 ÷ 14 = 4
Daniel's age now
= 9 u
= 9 x 4
= 36
Answer(s): 36
