Risa and Cindy had $161. Cindy had $5 more than Risa. Risa spent 3 times as much as Cindy and was left with
34 as much as Cindy. How much did Risa spend more than Cindy?
| |
Make p the same
(1)x4 = (3) |
Risa
(1) |
Cindy
(2) |
Make p the same
(2)x3 = (4) |
Total
|
Comparing Risa
and Cindy at first |
|
|
$5 more |
|
$161 |
| Before |
$312 |
$78 |
$83 |
$249 |
|
| Change |
- 12 u |
- 3 u |
- 1 u |
- 3 u |
|
| After |
12 p |
3 p |
4 p |
12 p |
|
Amount that Risa had at first
= (161 - 5) ÷ 2
= 156 ÷ 2
= $78
Amount that Cindy had at first
= 78 + 5
= $83
78 - 3 u = 3 p --- (1)
83 - 1 u = 4 p --- (2)
Make p the same.
(1)
x 4
312 - 12 u =
12 p --- (3)
(2)
x 3
249 - 3 u =
12 p --- (4)
(4) = (3)
249 - 3 u = 312 - 12 u
12 u - 3 u = 312 - 249
9 u = 63
1 u = 63 ÷ 9 = 7
Amount that Risa spent more than Cindy
= 3 u - 1 u
= 2 u
= 2 x 7
= $14
Answer(s): $14
