the answer is -$97 for sure.
- N; j& x! O2 Q8 @Think about it this way
) U. v7 P5 ]9 z6 T& g1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)
+ }; E2 D3 @9 v; S2) 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 |