the answer is -$97 for sure.
& k' r) v" U0 |& ?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。# J& k9 k& B5 q0 {0 x+ C8 z5 n
1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)公仔箱論壇8 {! y8 i& F+ c" w
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 |