Zoe and Diana had $94 at first. Zoe spent
47 of her money and Diana spent
23 of her money. Given that they had $78 left, how much did Zoe have at first?
|
Zoe |
Diana |
Total |
Before |
7 u |
3 p |
$94 |
Change |
- 4 u |
- 2 p |
|
After |
3 u |
1 p |
$78 |
7 u + 3 p = 94 --- (1)
3 u + 1 p = 78 --- (2)
(2) x 3 9 u + 3 p = 234 --- (3)
(3) - (1)
9 u - 7 u = 234 - 94
2 u = 140
1 u = 140 ÷ 2 = 70
Amount that Zoe had at first
= 7 u
= 7 x 70
= $490
Answer(s): $490