the answer is -$97 for sure.
% R6 w+ h/ V8 K0 L公仔箱論壇Think about it this way ' U8 }( F0 S1 s% H! r
1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)tvb now,tvbnow,bttvb% J2 h3 \9 r# b( v
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 |