Billy and Riordan have the same amount of money. If Billy spends $43 a day and Riordan spends $14 a day, Riordan will have $319 when Billy uses up all his money. If Billy spends $20 a day and Riordan spends $43 a day, how much will Billy have left when Riordan uses up all his money?
| |
Case 1 |
Case 2 |
| |
Billy |
Riordan |
Billy |
Riordan |
| Before |
43 u |
14 u + $319 |
43 u |
43 u |
| Change |
- 43 u |
- 14 u |
- 20 u |
- 43 u |
| After |
0 |
$319 |
23 u |
0 |
The amounts that Billy and Riordan 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 Billy will have left when Riordan uses up all his money
= 43 u - 20 u
= 23 u
= 23 x 11
= $253
Answer(s): $253
