The ratio of Luis's age to Elijah's age is 7 : 1. Last year, their average age was 11. How old will Elijah be in 8 years' time?
| |
Luis |
Elijah |
Total |
| Before |
7 u - 1 |
1 u - 1 |
22 |
| Change |
+ 1 |
+ 1 |
|
| After |
7 u |
1 u |
24 |
Total age of Luis and Elijah this year
= 7 u + 1 u
= 8 u
Total age of Luis and Elijah this year
= 2 x 11 + 1 + 1
= 22 + 2
= 24
8 u = 24
1 u = 24 ÷ 8 = 3
Elijah's age in 8 years' time
= 1 u + 8
= 1 x 3 + 8
= 3 + 8
= 11
Answer(s): 11
