The ratio of Warren's age to Ethan's age is 9 : 2. Last year, their average age was 21. How old will Ethan be in 2 years' time?
|
Warren |
Ethan |
Total |
Before |
9 u - 1 |
2 u - 1 |
42 |
Change |
+ 1 |
+ 1 |
|
After |
9 u |
2 u |
44 |
Total age of Warren and Ethan this year
= 9 u + 2 u
= 11 u
Total age of Warren and Ethan this year
= 2 x 21 + 1 + 1
= 42 + 2
= 44
11 u = 44
1 u = 44 ÷ 11 = 4
Ethan's age in 2 years' time
= 2 u + 2
= 2 x 4 + 2
= 8 + 2
= 10
Answer(s): 10