the answer is -$97 for sure. 公仔箱論壇; K$ M1 f: @1 ]$ w
Think about it this way tvb now,tvbnow,bttvb) g+ \' [# `! Q$ M7 J4 W" c
1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)TVBNOW 含有熱門話題,最新最快電視,軟體,遊戲,電影,動漫及日常生活及興趣交流等資訊。" r& A1 ^$ {' R9 R) P3 Z9 P
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 |