The ratio of Jack's age to Peter's age is 3 : 1. Last year, their average age was 13. How old will Peter be in 6 years' time?
| |
Jack |
Peter |
Total |
| Before |
3 u - 1 |
1 u - 1 |
26 |
| Change |
+ 1 |
+ 1 |
|
| After |
3 u |
1 u |
28 |
Total age of Jack and Peter this year
= 3 u + 1 u
= 4 u
Total age of Jack and Peter this year
= 2 x 13 + 1 + 1
= 26 + 2
= 28
4 u = 28
1 u = 28 ÷ 4 = 7
Peter's age in 6 years' time
= 1 u + 6
= 1 x 7 + 6
= 7 + 6
= 13
Answer(s): 13
