the answer is -$97 for sure. 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。" `' [ q" A( i0 J
Think about it this way
" j* O7 _: M2 D0 @- w公仔箱論壇1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)
8 T) P3 ?4 o, v3 H5.39.217.772) 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 |