The ratio of Will's age to Justin's age is 8 : 5. Last year, their average age was 12. How old will Justin be in 5 years' time?
| |
Will |
Justin |
Total |
| Before |
8 u - 1 |
5 u - 1 |
24 |
| Change |
+ 1 |
+ 1 |
|
| After |
8 u |
5 u |
26 |
Total age of Will and Justin this year
= 8 u + 5 u
= 13 u
Total age of Will and Justin this year
= 2 x 12 + 1 + 1
= 24 + 2
= 26
13 u = 26
1 u = 26 ÷ 13 = 2
Justin's age in 5 years' time
= 5 u + 5
= 5 x 2 + 5
= 10 + 5
= 15
Answer(s): 15
