PSLERisa and Esther went shopping together with a total amount of $120.60. Risa spent 2 times as much as Esther. The amount Esther had left was $21 more than what she had spent. She had 2 times as much money left as Risa.
(a) How much money did Esther spend?
(b) How much money did Risa have at first?
|
Risa |
Esther |
Total |
Before |
2.5 u + 10.5 |
2 u + 21 |
120.60 |
Change |
- 2 u |
- 1 u |
|
After |
0.5 u + 10.5 |
1 u + 21 |
|
(a)
Total amount that Risa and Esther had at first
= (2.5 u + 10.5) + (2 u + 21)
= 2.5 u + 2 u + 10.5 + 21
= 4.5 u + 31.5
4.5 u + 31.5 = 120.6
4.5 u = 120.6 - 31.5
4.5 u = 89.1
1 u = 89.1 ÷ 4.5 = 19.8
Amount that Esther had at first
= 1 u
= $19.80
(b)
Amount that Risa had at first
= 2.5 u + 10.5
= (2.5 x 19.8) + 10.5
= 49.5 + 10.5
= $60
Answer(s): (a) $19.80; (b) $60