Olivia and Sabrina had $143. Sabrina had $15 more than Olivia. Olivia spent 4 times as much as Sabrina and was left with
25 as much as Sabrina. How much did Olivia spend?
| |
Make p the same
(1)x5 = (3) |
Olivia
(1) |
Sabrina
(2) |
Make p the same
(2)x2 = (4) |
Total
|
Comparing Olivia
and Sabrina at first |
|
|
$15 more |
|
$143 |
| Before |
$320 |
$64 |
$79 |
$158 |
|
| Change |
- 20 u |
- 4 u |
- 1 u |
- 2 u |
|
| After |
10 p |
2 p |
5 p |
10 p |
|
Amount that Olivia had at first
= (143 - 15) ÷ 2
= 128 ÷ 2
= $64
Amount that Sabrina had at first
= 64 + 15
= $79
64 - 4 u = 2 p --- (1)
79 - 1 u = 5 p --- (2)
Make p the same.
(1)
x 5
320 - 20 u =
10 p --- (3)
(2)
x 2
158 - 2 u =
10 p --- (4)
(4) = (3)
158 - 2 u = 320 - 20 u
20 u - 2 u = 320 - 158
18 u = 162
1 u = 162 ÷ 18 = 9
Amount that Olivia spent
= 4 u
= 4 x 9
= $36
Answer(s): $36
