the answer is -$97 for sure.
6 n, r9 w' d, w* r% J( c4 WThink about it this way
1 Y3 M M$ s3 r" K5 c2 V5.39.217.771) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)
" g) v* Z+ P5 W2) 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 |