the answer is -$97 for sure.
$ Z3 I4 | d' u" y0 N0 Q! }5 `. cThink about it this way
j5 p9 I# Q% yTVBNOW 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。1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)公仔箱論壇: F( H& x; Z1 B5 h- O+ W+ `
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 |