The ratio of Fred's age to Carl's age is 8 : 3. Last year, their average age was 10. How old will Carl be in 3 years' time?
|
Fred |
Carl |
Total |
Before |
8 u - 1 |
3 u - 1 |
20 |
Change |
+ 1 |
+ 1 |
|
After |
8 u |
3 u |
22 |
Total age of Fred and Carl this year
= 8 u + 3 u
= 11 u
Total age of Fred and Carl this year
= 2 x 10 + 1 + 1
= 20 + 2
= 22
11 u = 22
1 u = 22 ÷ 11 = 2
Carl's age in 3 years' time
= 3 u + 3
= 3 x 2 + 3
= 6 + 3
= 9
Answer(s): 9