The ratio of Luis's age to John's age is 8 : 3. Next year, their average age will be 12. How old will Luis be in 2 years' time?
| |
Luis |
John |
Total |
| Before |
8 u |
3 u |
22 |
| Change |
+ 1 |
+ 1 |
|
| After |
8 u + 1 |
3 u + 1 |
24 |
Total age of Luis and John this year
= 8 u + 3 u
= 11 u
Total age of Luis and John this year
= 2 x 12 - 1 - 1
= 24 - 2
= 22
11 u = 22
1 u = 22 ÷ 11 = 2
Luis's age in 2 years' time
= 8 u + 2
= 8 x 2 + 2
= 16 + 2
= 18
Answer(s): 18
