The ratio of Henry's to Mark's money is 5 : 9. The ratio of Mark's to David's money is 3 : 4. If Henry has $80, how much more does David have than Mark?
| Henry |
Mark |
David |
| 5x1 |
9x1 |
|
| |
3x3 |
4x3 |
| 5 u |
9 u |
12 u |
The amount that Mark has is the repeated identity.
Use LCM to make it the same.
LCM of 9 and 3 = 9
Amount that Henry has = 5 u
5 u = 80
1 u = 80 ÷ 5 = 16
Amount that David has more than Mark
= 12 u - 9 u
= 3 u
= 3 x 16
= $48
Answer(s): $48
