John's current age is 9 times as old as Rael's age years ago. Today, Rael's age is John's age the same number of years ago. How old is John's age now if the total of their current age is 70?
| |
John |
Rael |
Difference |
Total |
| Before |
1 p |
1 u |
1 p - 1 u |
|
| Change |
+ ? |
+ ? |
|
|
| After |
9 u |
1 p |
9 u - 1 p |
70 |
Total age of John and Rael today = 9 u + 1 p
9 u + 1 p = 70 --- (1)
The difference in John's age and Rael'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 = 70
9 u + 5 u = 70
14 u = 70
1 u = 70 ÷ 14 = 5
John's age now
= 9 u
= 9 x 5
= 45
Answer(s): 45
