Dana and Linda had $200. Linda had $20 more than Dana. Dana spent 3 times as much as Linda and was left with
35 as much as Linda. How much did Dana spend?
| |
Make p the same
(1)x5 = (3) |
Dana
(1) |
Linda
(2) |
Make p the same
(2)x3 = (4) |
Total
|
Comparing Dana
and Linda at first |
|
|
$20 more |
|
$200 |
| Before |
$450 |
$90 |
$110 |
$330 |
|
| Change |
- 15 u |
- 3 u |
- 1 u |
- 3 u |
|
| After |
15 p |
3 p |
5 p |
15 p |
|
Amount that Dana had at first
= (200 - 20) ÷ 2
= 180 ÷ 2
= $90
Amount that Linda had at first
= 90 + 20
= $110
90 - 3 u = 3 p --- (1)
110 - 1 u = 5 p --- (2)
Make p the same.
(1)
x 5
450 - 15 u =
15 p --- (3)
(2)
x 3
330 - 3 u =
15 p --- (4)
(4) = (3)
330 - 3 u = 450 - 15 u
15 u - 3 u = 450 - 330
12 u = 120
1 u = 120 ÷ 12 = 10
Amount that Dana spent
= 3 u
= 3 x 10
= $30
Answer(s): $30
