the answer is -$97 for sure.
& m; E- g# P- _2 A6 N9 ~1 yThink about it this way
& S" ]; D8 k, g! C4 [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。1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)公仔箱論壇% J1 Y( k) P/ u3 z
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 |