The ratio of Tom's age to Zeph's age is 3 : 1. Last year, their average age was 17. How old will Zeph be in 8 years' time?
| |
Tom |
Zeph |
Total |
| Before |
3 u - 1 |
1 u - 1 |
34 |
| Change |
+ 1 |
+ 1 |
|
| After |
3 u |
1 u |
36 |
Total age of Tom and Zeph this year
= 3 u + 1 u
= 4 u
Total age of Tom and Zeph this year
= 2 x 17 + 1 + 1
= 34 + 2
= 36
4 u = 36
1 u = 36 ÷ 4 = 9
Zeph's age in 8 years' time
= 1 u + 8
= 1 x 9 + 8
= 9 + 8
= 17
Answer(s): 17
