the answer is -$97 for sure. 公仔箱論壇' {" ]" n# L) D$ _9 X
Think about it this way 公仔箱論壇% l, m& H- u" a' x/ Q
1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)5 q/ S$ |& J, O4 t5 r5 j
2) Now, the owner discovered that the 100 bucks is fake. You can think this as a lost of $100. therefore the overall gain is $3-$100 = -$97 |
發表於 2007-5-16 03:12 AM
| 
發表於 2007-5-19 03:21 PM
| 
發表於 2007-5-21 03:49 AM
| 