the answer is -$97 for sure.
1 f1 V, f: T2 Z. D$ E2 s公仔箱論壇Think about it this way TVBNOW 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。4 W) c6 U, ~* H
1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)
) Z$ ]2 A6 }1 C+ ^; a- z公仔箱論壇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 |