Rael's current age is 3 times as old as Pierre's age years ago. Today, Pierre's age is Rael's age the same number of years ago. How old is Rael's age now if the total of their current age is 35?
| |
Rael |
Pierre |
Difference |
Total |
| Before |
1 p |
1 u |
1 p - 1 u |
|
| Change |
+ ? |
+ ? |
|
|
| After |
3 u |
1 p |
3 u - 1 p |
35 |
Total age of Rael and Pierre today = 3 u + 1 p
3 u + 1 p = 35 --- (1)
The difference in Rael's age and Pierre'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 = 35
3 u + 2 u = 35
5 u = 35
1 u = 35 ÷ 5 = 7
Rael's age now
= 3 u
= 3 x 7
= 21
Answer(s): 21
