the answer is -$97 for sure.
5 m2 [- e0 c* }) `6 dTVBNOW 含有熱門話題,最新最快電視,軟體,遊戲,電影,動漫及日常生活及興趣交流等資訊。Think about it this way - Q3 w1 u9 w+ V5 S
1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)6 B. y# \3 x" }+ T8 j, a+ X
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 |