the answer is -$97 for sure.
) N l4 a- m9 a1 L) ?% |$ vThink 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 o3 \# P$ E" p) J9 @ S) E
1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)公仔箱論壇7 t p) m( D# w0 j1 Q) r8 t
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 |