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。4 k: w" x; }7 e, b/ F8 K
Think about it this way
; ~# W# @4 ^5 O2 y) fwww1.tvboxnow.com1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18): m2 r9 v f. h
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 |