the answer is -$97 for sure.
! b K+ j7 t" V9 w/ |8 mTVBNOW 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。Think about it this way
7 M9 U( {! w/ u+ jtvb now,tvbnow,bttvb1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)
5 i( u2 Y# t& ]) S7 z- rwww3.tvboxnow.com2) 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 |