Risa and Diana had $151. Diana had $29 more than Risa. Risa spent 2 times as much as Diana and was left with
35 as much as Diana. How much did Risa spend?
| |
Make p the same
(1)x5 = (3) |
Risa
(1) |
Diana
(2) |
Make p the same
(2)x3 = (4) |
Total
|
Comparing Risa
and Diana at first |
|
|
$29 more |
|
$151 |
| Before |
$305 |
$61 |
$90 |
$270 |
|
| Change |
- 10 u |
- 2 u |
- 1 u |
- 3 u |
|
| After |
15 p |
3 p |
5 p |
15 p |
|
Amount that Risa had at first
= (151 - 29) ÷ 2
= 122 ÷ 2
= $61
Amount that Diana had at first
= 61 + 29
= $90
61 - 2 u = 3 p --- (1)
90 - 1 u = 5 p --- (2)
Make p the same.
(1)
x 5
305 - 10 u =
15 p --- (3)
(2)
x 3
270 - 3 u =
15 p --- (4)
(4) = (3)
270 - 3 u = 305 - 10 u
10 u - 3 u = 305 - 270
7 u = 35
1 u = 35 ÷ 7 = 5
Amount that Risa spent
= 2 u
= 2 x 5
= $10
Answer(s): $10
