原帖由 prozzy 於 2007-5-18 23:05 發表。 : ]7 k; c# |6 _& t* B
the answer is -$97 for sure. 9 t. k! ~/ L! J6 q F# [. n
Think about it this way - Y( h1 Q$ W& J) O6 R: ?
1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)5.39.217.76" m+ W& n" {/ s4 w5 C' J6 ?
2) Now, the owner discovered that the 100 bucks is fake. You can th ... 公仔箱論壇# `4 ~. L2 _" h4 C0 N0 S
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+ V! R$ @$ P" \) ]; G* h3 I6 D1) very good, it the 100 bucks is real, your answer is correct, but it is fake, so your answer is wrong2 ]4 w: G. r2 B4 C, j3 t
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think about it, when the bill is fake, and he gave him $79 change back, that is -79 already, it means the 100 on his hand is equal to 0 (Zero), how did he makes profit when he got a fake bills, then he need to pay another real 100 dollars bill to his neighbor, that another -100, plus the product he lost, thats another 18 dollars, Do Not Even Mention the 3 dollars, there is no profit he can make when he got a fake bill.
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+ Z5 ]' r! ~# K5 R公仔箱論壇I know the answer becoz it really happening to my friend in his store in real LIFE, it can not be wrong. |