The ratio of Michael's age to Oliver's age is 4 : 3. Last year, their average age was 20. How old will Oliver be in 12 years' time?
|
Michael |
Oliver |
Total |
Before |
4 u - 1 |
3 u - 1 |
40 |
Change |
+ 1 |
+ 1 |
|
After |
4 u |
3 u |
42 |
Total age of Michael and Oliver this year
= 4 u + 3 u
= 7 u
Total age of Michael and Oliver this year
= 2 x 20 + 1 + 1
= 40 + 2
= 42
7 u = 42
1 u = 42 ÷ 7 = 6
Oliver's age in 12 years' time
= 3 u + 12
= 3 x 6 + 12
= 18 + 12
= 30
Answer(s): 30