the answer is -$97 for sure.
3 y, J4 y" M8 U! Y- r公仔箱論壇Think about it this way 公仔箱論壇$ S, o; T4 f. d: M: ?5 @
1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)
1 {0 @/ }/ @- H/ V& xtvb 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 |