The ratio of Archie's to Tom's money is 7 : 4. The ratio of Tom's to Riordan's money is 3 : 4. If Archie has $399, how much less does Tom have than Riordan?
| Archie |
Tom |
Riordan |
| 7x3 |
4x3 |
|
| |
3x4 |
4x4 |
| 21 u |
12 u |
16 u |
The amount that Tom has is the repeated identity.
Use LCM to make it the same.
LCM of 4 and 3 = 12
Amount that Archie has = 21 u
21 u = 399
1 u = 399 ÷ 21 = 19
Amount that Tom has less than Riordan
= 16 u - 12 u
= 4 u
= 4 x 19
= $76
Answer(s): $76
