Risa went shopping with thrice as much money as Cathy. After Risa spent $1100, Cathy had four times as much money as Risa had left. How much more money did Risa bring along for shopping than Cathy?
| |
Risa |
Cathy |
Difference |
| Before |
3x4 =
12 u |
1x4 =
4 u |
8 u |
| Change |
- $1100 |
|
|
| After |
1 u |
4 u |
|
The amount that Cathy has remains unchanged at first and in the end. Make the amount that Cathy has the same. LCM of 1 and 4 is 4.
Amount that Risa spent
= 12 u - 1 u
= 11 u
11 u = 1100
1 u = 1100 ÷ 11 = 100
Amount that Risa brought along more than Cathy
= 12 u - 4 u
= 8 u
= 8 x 100
= $800
Answer(s): $800
