The ratio of Justin's to Seth's money is 7 : 9. The ratio of Seth's to Ahmad's money is 3 : 4. If Justin has $105, how much less does Seth have than Ahmad?
| Justin |
Seth |
Ahmad |
| 7x1 |
9x1 |
|
| |
3x3 |
4x3 |
| 7 u |
9 u |
12 u |
The amount that Seth has is the repeated identity.
Use LCM to make it the same.
LCM of 9 and 3 = 9
Amount that Justin has = 7 u
7 u = 105
1 u = 105 ÷ 7 = 15
Amount that Seth has less than Ahmad
= 12 u - 9 u
= 3 u
= 3 x 15
= $45
Answer(s): $45
