the answer is -$97 for sure. 公仔箱論壇 H" C6 j, c# I9 Q
Think about it this way 5.39.217.76& W5 F% ^" W2 b5 o
1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)
|- k0 M4 R, s3 o1 {. b7 i4 S2) 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 |
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