Zoe and Fiona had $77 at first. Zoe spent
37 of her money and Fiona spent
45 of her money. Given that they had $31 left, how much did Zoe have at first?
|
Zoe |
Fiona |
Total |
Before |
7 u |
5 p |
$77 |
Change |
- 3 u |
- 4 p |
|
After |
4 u |
1 p |
$31 |
7 u + 5 p = 77 --- (1)
4 u + 1 p = 31 --- (2)
(2) x 5 20 u + 5 p = 155 --- (3)
(3) - (1)
20 u - 7 u = 155 - 77
13 u = 78
1 u = 78 ÷ 13 = 6
Amount that Zoe had at first
= 7 u
= 7 x 6
= $42
Answer(s): $42