David and Vincent have the same amount of money. If David spends $43 a day and Vincent spends $14 a day, Vincent will have $319 when David uses up all his money. If David spends $18 a day and Vincent spends $43 a day, how much will David have left when Vincent uses up all his money?
| |
Case 1 |
Case 2 |
| |
David |
Vincent |
David |
Vincent |
| Before |
43 u |
14 u + $319 |
43 u |
43 u |
| Change |
- 43 u |
- 14 u |
- 18 u |
- 43 u |
| After |
0 |
$319 |
25 u |
0 |
The amounts that David and Vincent have at first are the same.
43 u = 14 u + 319
43 u - 14 u = 319
29 u = 319
1 u = 319 ÷ 29 = 11
Amount that David will have left when Vincent uses up all his money
= 43 u - 18 u
= 25 u
= 25 x 11
= $275
Answer(s): $275
