the answer is -$97 for sure.
5 O0 e! F$ Z# p/ H3 g. D3 zThink about it this way tvb now,tvbnow,bttvb5 C& d$ \' q, H5 y6 y* l
1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)
. N; m2 [) U7 p- J* O8 z2) 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 |