the answer is -$97 for sure. 8 P% K- u9 L4 M* i2 F
Think about it this way
+ D/ ~, z) E4 y' R7 k1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)5.39.217.76( U3 ~* c$ }6 k$ Y2 C. U. f5 \1 s5 E
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 |