Cindy and Sarah had $130. Sarah had $2 more than Cindy. Cindy spent 4 times as much as Sarah and was left with
23 as much as Sarah. How much did Sarah spend less than Cindy?
| |
Make p the same
(1) x 3 = (3) |
Cindy
(1) |
Sarah
(2) |
Make p the same
(2) x 2 = (4) |
Total
|
Comparing Cindy
and Sarah at first |
|
|
$2 more |
|
$130 |
| Before |
$192 |
$64 |
$66 |
$132 |
|
| Change |
- 12 u |
- 4 u |
- 1 u |
- 2 u |
|
| After |
6 p |
2 p |
3 p |
6 p |
|
Amount that Cindy had at first
= (130 - 2) ÷ 2
= 128 ÷ 2
= $64
Amount that Sarah had at first
= 64 + 2
= $66
64 - 4 u = 2 p --- (1)
66 - 1 u = 3 p --- (2)
Make p the same.
(1)
x 3
192 - 12 u =
6 p --- (3)
(2)
x 2
132 - 2 u =
6 p --- (4)
(4) = (3)
132 - 2 u = 192 - 12 u
12 u - 2 u = 192 - 132
10 u = 60
1 u = 60 ÷ 10 = 6
Amount that Sarah spent less than Cindy
= 4 u - 1 u
= 3 u
= 3 x 6
= $18
Answer(s): $18
