The ratio of Peter's age to Jenson's age is 4 : 3. Next year, their average age will be 15. How old will Peter be in 9 years' time?
| |
Peter |
Jenson |
Total |
| Before |
4 u |
3 u |
28 |
| Change |
+ 1 |
+ 1 |
|
| After |
4 u + 1 |
3 u + 1 |
30 |
Total age of Peter and Jenson this year
= 4 u + 3 u
= 7 u
Total age of Peter and Jenson this year
= 2 x 15 - 1 - 1
= 30 - 2
= 28
7 u = 28
1 u = 28 ÷ 7 = 4
Peter's age in 9 years' time
= 4 u + 9
= 4 x 4 + 9
= 16 + 9
= 25
Answer(s): 25
