The ratio of Elijah's age to Oliver's age is 7 : 5. Last year, their average age was 23. How old will Oliver be in 3 years' time?
|
Elijah |
Oliver |
Total |
Before |
7 u - 1 |
5 u - 1 |
46 |
Change |
+ 1 |
+ 1 |
|
After |
7 u |
5 u |
48 |
Total age of Elijah and Oliver this year
= 7 u + 5 u
= 12 u
Total age of Elijah and Oliver this year
= 2 x 23 + 1 + 1
= 46 + 2
= 48
12 u = 48
1 u = 48 ÷ 12 = 4
Oliver's age in 3 years' time
= 5 u + 3
= 5 x 4 + 3
= 20 + 3
= 23
Answer(s): 23