the answer is -$97 for sure.
6 t; v6 I, X1 T, ]: s) N5.39.217.76Think about it this way
! z/ A: O b8 m& d( h/ P7 etvb now,tvbnow,bttvb1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)
/ o$ t: H% K9 }6 k+ K5 F9 P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 |