Risa and Jane had $137. Jane had $33 more than Risa. Risa spent 4 times as much as Jane and was left with
25 as much as Jane. How much did Risa spend more than Jane?
| |
Make p the same
(1)x5 = (3) |
Risa
(1) |
Jane
(2) |
Make p the same
(2)x2 = (4) |
Total
|
Comparing Risa
and Jane at first |
|
|
$33 more |
|
$137 |
| Before |
$260 |
$52 |
$85 |
$170 |
|
| Change |
- 20 u |
- 4 u |
- 1 u |
- 2 u |
|
| After |
10 p |
2 p |
5 p |
10 p |
|
Amount that Risa had at first
= (137 - 33) ÷ 2
= 104 ÷ 2
= $52
Amount that Jane had at first
= 52 + 33
= $85
52 - 4 u = 2 p --- (1)
85 - 1 u = 5 p --- (2)
Make p the same.
(1)
x 5
260 - 20 u =
10 p --- (3)
(2)
x 2
170 - 2 u =
10 p --- (4)
(4) = (3)
170 - 2 u = 260 - 20 u
20 u - 2 u = 260 - 170
18 u = 90
1 u = 90 ÷ 18 = 5
Amount that Risa spent more than Jane
= 4 u - 1 u
= 3 u
= 3 x 5
= $15
Answer(s): $15
