the answer is -$97 for sure. 公仔箱論壇+ D- ~- n2 w7 F" w
Think about it this way
1 d: h7 h2 y3 Q W! x1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)tvb now,tvbnow,bttvb4 g3 k3 ^' y# X# z
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 |