PSLEGillian and Risa went shopping together with a total amount of $90.60. Gillian spent 2 times as much as Risa. The amount Risa had left was $25 more than what she had spent. She had 2 times as much money left as Gillian.
(a) How much money did Risa spend?
(b) How much money did Gillian have at first?
|
Gillian |
Risa |
Total |
Before |
2.5 u + 12.5 |
2 u + 25 |
90.60 |
Change |
- 2 u |
- 1 u |
|
After |
0.5 u + 12.5 |
1 u + 25 |
|
(a)
Total amount that Gillian and Risa had at first
= (2.5 u + 12.5) + (2 u + 25)
= 2.5 u + 2 u + 12.5 + 25
= 4.5 u + 37.5
4.5 u + 37.5 = 90.6
4.5 u = 90.6 - 37.5
4.5 u = 53.1
1 u = 53.1 ÷ 4.5 = 11.8
Amount that Risa had at first
= 1 u
= $11.80
(b)
Amount that Gillian had at first
= 2.5 u + 12.5
= (2.5 x 11.8) + 12.5
= 29.5 + 12.5
= $42
Answer(s): (a) $11.80; (b) $42