the answer is -$97 for sure. tvb now,tvbnow,bttvb# c: v% A9 R" J9 a* W: o
Think about it this way
2 U2 A; z# I2 |/ A5 g% C公仔箱論壇1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)公仔箱論壇: _2 x8 t3 I6 `7 i# n8 Y8 q$ t
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 |