The ratio of Ian's age to Vaidev's age is 3 : 1. Last year, their average age was 21. How old will Vaidev be in 9 years' time?
| |
Ian |
Vaidev |
Total |
| Before |
3 u - 1 |
1 u - 1 |
42 |
| Change |
+ 1 |
+ 1 |
|
| After |
3 u |
1 u |
44 |
Total age of Ian and Vaidev this year
= 3 u + 1 u
= 4 u
Total age of Ian and Vaidev this year
= 2 x 21 + 1 + 1
= 42 + 2
= 44
4 u = 44
1 u = 44 ÷ 4 = 11
Vaidev's age in 9 years' time
= 1 u + 9
= 1 x 11 + 9
= 11 + 9
= 20
Answer(s): 20
