The ratio of Simon's to Mark's money is 5 : 7. The ratio of Mark's to Riordan's money is 3 : 4. If Simon has $180, how much more does Riordan have than Mark?
| Simon |
Mark |
Riordan |
| 5x3 |
7x3 |
|
| |
3x7 |
4x7 |
| 15 u |
21 u |
28 u |
The amount that Mark has is the repeated identity.
Use LCM to make it the same.
LCM of 7 and 3 = 21
Amount that Simon has = 15 u
15 u = 180
1 u = 180 ÷ 15 = 12
Amount that Riordan has more than Mark
= 28 u - 21 u
= 7 u
= 7 x 12
= $84
Answer(s): $84
