The ratio of Seth's age to Luke's age is 7 : 3. Next year, their average age will be 11. How old will Seth be in 12 years' time?
| |
Seth |
Luke |
Total |
| Before |
7 u |
3 u |
20 |
| Change |
+ 1 |
+ 1 |
|
| After |
7 u + 1 |
3 u + 1 |
22 |
Total age of Seth and Luke this year
= 7 u + 3 u
= 10 u
Total age of Seth and Luke this year
= 2 x 11 - 1 - 1
= 22 - 2
= 20
10 u = 20
1 u = 20 ÷ 10 = 2
Seth's age in 12 years' time
= 7 u + 12
= 7 x 2 + 12
= 14 + 12
= 26
Answer(s): 26
