The ratio of Sean's age to Nick's age is 7 : 2. Next year, their average age will be 10. How old will Sean be in 11 years' time?
| |
Sean |
Nick |
Total |
| Before |
7 u |
2 u |
18 |
| Change |
+ 1 |
+ 1 |
|
| After |
7 u + 1 |
2 u + 1 |
20 |
Total age of Sean and Nick this year
= 7 u + 2 u
= 9 u
Total age of Sean and Nick this year
= 2 x 10 - 1 - 1
= 20 - 2
= 18
9 u = 18
1 u = 18 ÷ 9 = 2
Sean's age in 11 years' time
= 7 u + 11
= 7 x 2 + 11
= 14 + 11
= 25
Answer(s): 25
