Oscar's current age is 7 times as old as Ryan's age years ago. Today, Ryan's age is Oscar's age the same number of years ago. How old is Ryan's age now if the total of their current age is 55?
|
Oscar |
Ryan |
Difference |
Total |
Before |
1 p |
1 u |
1 p - 1 u |
|
Change |
+ ? |
+ ? |
|
|
After |
7 u |
1 p |
7 u - 1 p |
55 |
Total age of Oscar and Ryan today = 7 u + 1 p
7 u + 1 p = 55 --- (1)
The difference in Oscar's age and Ryan'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 = 55
7 u + 4 u = 55
11 u = 55
1 u = 55 ÷ 11 = 5
Oscar's age now
= 55 - 7 u
= 55 - 7 x 5
= 55 - 35
= 20
Answer(s): 20