The ratio of Will's age to Pierre's age is 5 : 3. Last year, their average age was 19. How old will Pierre be in 3 years' time?
| |
Will |
Pierre |
Total |
| Before |
5 u - 1 |
3 u - 1 |
38 |
| Change |
+ 1 |
+ 1 |
|
| After |
5 u |
3 u |
40 |
Total age of Will and Pierre this year
= 5 u + 3 u
= 8 u
Total age of Will and Pierre this year
= 2 x 19 + 1 + 1
= 38 + 2
= 40
8 u = 40
1 u = 40 ÷ 8 = 5
Pierre's age in 3 years' time
= 3 u + 3
= 3 x 5 + 3
= 15 + 3
= 18
Answer(s): 18
