the answer is -$97 for sure. 公仔箱論壇' h9 y4 P8 H {
Think about it this way
& j& s: `2 X2 O! bTVBNOW 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)3 L6 z( G4 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 |