the answer is -$97 for sure.
0 S9 _+ }1 [8 Z公仔箱論壇Think about it this way
/ j" K. ?8 A- ^' j H+ u7 Z: j! y# i6 mtvb now,tvbnow,bttvb1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)TVBNOW 含有熱門話題,最新最快電視,軟體,遊戲,電影,動漫及日常生活及興趣交流等資訊。7 u9 D$ ]% H) m3 z- G- A
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 |