prozzy

the answer is -$97 for sure.
0 B: ^; L+ L  X8 u) W* x5.39.217.77Think about it this way
& l* Q0 B$ b; c: }& Y! g1 X( w1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)5.39.217.77& p' [, {) B6 j3 V, m: ]
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