The ratio of Carl's age to Daniel's age is 7 : 2. Last year, their average age was 17. How old will Daniel be in 9 years' time?
| |
Carl |
Daniel |
Total |
| Before |
7 u - 1 |
2 u - 1 |
34 |
| Change |
+ 1 |
+ 1 |
|
| After |
7 u |
2 u |
36 |
Total age of Carl and Daniel this year
= 7 u + 2 u
= 9 u
Total age of Carl and Daniel this year
= 2 x 17 + 1 + 1
= 34 + 2
= 36
9 u = 36
1 u = 36 ÷ 9 = 4
Daniel's age in 9 years' time
= 2 u + 9
= 2 x 4 + 9
= 8 + 9
= 17
Answer(s): 17
