the answer is -$97 for sure. $ t8 F! m0 W5 d) ^8 \
Think about it this way
! v* m( n* D7 O! @8 ?5.39.217.771) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)
: U7 W1 w5 T( y+ ], ?. J7 H! p9 {tvb now,tvbnow,bttvb2) 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 |