the answer is -$97 for sure.
b' S# u7 x% t* c9 iThink about it this way tvb now,tvbnow,bttvb v( u! t8 v! ^# p) X
1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)5.39.217.76) v: Q8 c8 C0 D
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 |