Fred's current age is 3 times as old as Brandon's age years ago. Today, Brandon's age is Fred's age the same number of years ago. How old is Brandon's age now if the total of their current age is 10?
| |
Fred |
Brandon |
Difference |
Total |
| Before |
1 p |
1 u |
1 p - 1 u |
|
| Change |
+ ? |
+ ? |
|
|
| After |
3 u |
1 p |
3 u - 1 p |
10 |
Total age of Fred and Brandon today = 3 u + 1 p
3 u + 1 p = 10 --- (1)
The difference in Fred's age and Brandon'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 = 10
3 u + 2 u = 10
5 u = 10
1 u = 10 ÷ 5 = 2
Fred's age now
= 10 - 3 u
= 10 - 3 x 2
= 10 - 6
= 4
Answer(s): 4
