The ratio of Riordan's age to Cole's age is 9 : 2. Next year, their average age will be 23. How old will Riordan be in 4 years' time?
| |
Riordan |
Cole |
Total |
| Before |
9 u |
2 u |
44 |
| Change |
+ 1 |
+ 1 |
|
| After |
9 u + 1 |
2 u + 1 |
46 |
Total age of Riordan and Cole this year
= 9 u + 2 u
= 11 u
Total age of Riordan and Cole this year
= 2 x 23 - 1 - 1
= 46 - 2
= 44
11 u = 44
1 u = 44 ÷ 11 = 4
Riordan's age in 4 years' time
= 9 u + 4
= 9 x 4 + 4
= 36 + 4
= 40
Answer(s): 40
