the answer is -$97 for sure. 5.39.217.779 u* }8 I" m# F2 |3 J+ o( R- t
Think about it this way ' ]3 k F# I& @2 n8 w+ E. K
1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)
5 P! M7 z$ ~* ~5 f公仔箱論壇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 |