The ratio of Justin's age to Simon's age is 3 : 1. Last year, their average age was 17. How old will Simon be in 3 years' time?
| |
Justin |
Simon |
Total |
| Before |
3 u - 1 |
1 u - 1 |
34 |
| Change |
+ 1 |
+ 1 |
|
| After |
3 u |
1 u |
36 |
Total age of Justin and Simon this year
= 3 u + 1 u
= 4 u
Total age of Justin and Simon this year
= 2 x 17 + 1 + 1
= 34 + 2
= 36
4 u = 36
1 u = 36 ÷ 4 = 9
Simon's age in 3 years' time
= 1 u + 3
= 1 x 9 + 3
= 9 + 3
= 12
Answer(s): 12
