The ratio of John's age to Perry's age is 2 : 1. Last year, their average age was 17. How old will Perry be in 3 years' time?
|
John |
Perry |
Total |
Before |
2 u - 1 |
1 u - 1 |
34 |
Change |
+ 1 |
+ 1 |
|
After |
2 u |
1 u |
36 |
Total age of John and Perry this year
= 2 u + 1 u
= 3 u
Total age of John and Perry this year
= 2 x 17 + 1 + 1
= 34 + 2
= 36
3 u = 36
1 u = 36 ÷ 3 = 12
Perry's age in 3 years' time
= 1 u + 3
= 1 x 12 + 3
= 12 + 3
= 15
Answer(s): 15