Oliver's current age is 9 times as old as Andy's age years ago. Today, Andy's age is Oliver's age the same number of years ago. How old is Oliver's age now if the total of their current age is 42?
| |
Oliver |
Andy |
Difference |
Total |
| Before |
1 p |
1 u |
1 p - 1 u |
|
| Change |
+ ? |
+ ? |
|
|
| After |
9 u |
1 p |
9 u - 1 p |
42 |
Total age of Oliver and Andy today = 9 u + 1 p
9 u + 1 p = 42 --- (1)
The difference in Oliver's age and Andy'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 = 42
9 u + 5 u = 42
14 u = 42
1 u = 42 ÷ 14 = 3
Oliver's age now
= 9 u
= 9 x 3
= 27
Answer(s): 27
