原帖由 prozzy 於 2007-5-18 23:05 發表。 
4 _% [ |; _: v. X& U& Y1 v5.39.217.76the answer is -$97 for sure.
3 k" a4 M+ s7 r) G0 e% ]5 V0 OThink about it this way
; k; |! {# F' _& [7 E; E1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)
5 V8 w- ~1 |9 M5.39.217.762) Now, the owner discovered that the 100 bucks is fake. You can th ... 2 t' i9 }/ M, H
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1) very good, it the 100 bucks is real, your answer is correct, but it is fake, so your answer is wrong
' n4 b8 j5 w! ^/ D7 O N$ Dtvb now,tvbnow,bttvb
, h& C5 ]3 M$ Itvb now,tvbnow,bttvbthink 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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I know the answer becoz it really happening to my friend in his store in real LIFE, it can not be wrong. |