the answer is -$97 for sure.
' N) j' T3 W& [. T5.39.217.76Think about it this way 公仔箱論壇! \- [& b4 @1 k V4 @; Q h
1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)
5 ?, L9 c6 W0 `# A8 I& F5 j+ u3 ~, ^tvb now,tvbnow,bttvb2) 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 |