Gabby went shopping with thrice as much money as Mary. After Gabby spent $220, Mary had four times as much money as Gabby had left. How much less money did Mary bring along for shopping than Gabby?
| |
Gabby |
Mary |
Difference |
| Before |
3x4 =
12 u |
1x4 =
4 u |
8 u |
| Change |
- $220 |
|
|
| After |
1 u |
4 u |
|
The amount that Mary has remains unchanged at first and in the end. Make the amount that Mary has the same. LCM of 1 and 4 is 4.
Amount that Gabby spent
= 12 u - 1 u
= 11 u
11 u = 220
1 u = 220 ÷ 11 = 20
Amount that Mary brought along less than Gabby
= 12 u - 4 u
= 8 u
= 8 x 20
= $160
Answer(s): $160
