Risa and Min had $161. Min had $43 more than Risa. Risa spent 3 times as much as Min and was left with
25 as much as Min. How much did Risa spend?
| |
Make p the same
(1)x5 = (3) |
Risa
(1) |
Min
(2) |
Make p the same
(2)x2 = (4) |
Total
|
Comparing Risa
and Min at first |
|
|
$43 more |
|
$161 |
| Before |
$295 |
$59 |
$102 |
$204 |
|
| Change |
- 15 u |
- 3 u |
- 1 u |
- 2 u |
|
| After |
10 p |
2 p |
5 p |
10 p |
|
Amount that Risa had at first
= (161 - 43) ÷ 2
= 118 ÷ 2
= $59
Amount that Min had at first
= 59 + 43
= $102
59 - 3 u = 2 p --- (1)
102 - 1 u = 5 p --- (2)
Make p the same.
(1)
x 5
295 - 15 u =
10 p --- (3)
(2)
x 2
204 - 2 u =
10 p --- (4)
(4) = (3)
204 - 2 u = 295 - 15 u
15 u - 2 u = 295 - 204
13 u = 91
1 u = 91 ÷ 13 = 7
Amount that Risa spent
= 3 u
= 3 x 7
= $21
Answer(s): $21
