The ratio of Andy's age to Tom's age is 9 : 2. Last year, their average age was 21. How old will Tom be in 8 years' time?
| |
Andy |
Tom |
Total |
| Before |
9 u - 1 |
2 u - 1 |
42 |
| Change |
+ 1 |
+ 1 |
|
| After |
9 u |
2 u |
44 |
Total age of Andy and Tom this year
= 9 u + 2 u
= 11 u
Total age of Andy and Tom this year
= 2 x 21 + 1 + 1
= 42 + 2
= 44
11 u = 44
1 u = 44 ÷ 11 = 4
Tom's age in 8 years' time
= 2 u + 8
= 2 x 4 + 8
= 8 + 8
= 16
Answer(s): 16
