The ratio of David's age to Brandon's age is 5 : 1. Next year, their average age will be 19. How old will David be in 8 years' time?
| |
David |
Brandon |
Total |
| Before |
5 u |
1 u |
36 |
| Change |
+ 1 |
+ 1 |
|
| After |
5 u + 1 |
1 u + 1 |
38 |
Total age of David and Brandon this year
= 5 u + 1 u
= 6 u
Total age of David and Brandon this year
= 2 x 19 - 1 - 1
= 38 - 2
= 36
6 u = 36
1 u = 36 ÷ 6 = 6
David's age in 8 years' time
= 5 u + 8
= 5 x 6 + 8
= 30 + 8
= 38
Answer(s): 38
