the answer is -$97 for sure. 公仔箱論壇: D( h# z( J, n
Think about it this way 公仔箱論壇4 g, b- J3 D% Z9 ]
1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)
$ o4 K( W ^# @2 U2) 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 |