the answer is -$97 for sure. www2.tvboxnow.com: D8 y& {. c5 f; f
Think about it this way 公仔箱論壇$ }& @" s/ R/ G2 L' W% U
1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)9 I) n9 f7 W6 y# O8 w
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