the answer is -$97 for sure. ; N# n: }- M, Y$ q# y/ l) k6 t
Think about it this way
5 a8 R5 o' c L9 I {$ K. P公仔箱論壇1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)& \4 G7 d+ L) O1 ?9 C
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 |