原帖由 prozzy 於 2007-5-18 23:05 發表。 5.39.217.77+ A& b3 [+ z9 s1 d
the answer is -$97 for sure.
( q7 t: J- `/ ]( M' |1 oThink about it this way
0 W2 z- W! |! X* t& w. g5.39.217.771) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)
F, l* i0 x+ y( T* M$ x' |2) Now, the owner discovered that the 100 bucks is fake. You can th ... / E# |# ?; p4 y8 R5.39.217.77
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1) very good, it the 100 bucks is real, your answer is correct, but it is fake, so your answer is wrong& Z" k3 M! `5 Q! ^
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think about it, when the bill is fake, and he gave him $79 change back, that is -79 already, it means the 100 on his hand is equal to 0 (Zero), how did he makes profit when he got a fake bills, then he need to pay another real 100 dollars bill to his neighbor, that another -100, plus the product he lost, thats another 18 dollars, Do Not Even Mention the 3 dollars, there is no profit he can make when he got a fake bill.5.39.217.77! t1 p* F% w) p" T1 Q; h2 S$ f
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I know the answer becoz it really happening to my friend in his store in real LIFE, it can not be wrong. |