the answer is -$97 for sure.
- J* T1 j3 f: Q% v' n2 Q+ GThink about it this way 5.39.217.777 o# G' A- q* e% ]% n+ }9 x, Y
1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)
/ E+ p6 w. v4 P A3 _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 |