the answer is -$97 for sure.
& F! H1 |7 n. Y5 _3 x7 gThink 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。- c# ]+ X6 j, I" g5 B
1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)tvb now,tvbnow,bttvb \+ n7 P9 e+ Q, c: g4 ?" ]3 d- s
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 |