原帖由 prozzy 於 2007-5-18 23:05 發表。 
1 U# N) `- T& f/ G( [5.39.217.76the answer is -$97 for sure. ) Q3 b# d' l- K$ B) |8 {5 n# D
Think about it this way s& j8 O: U# Q2 k/ l, a+ `
1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)1 O! a* a! C% S3 X1 }' l, Z
2) Now, the owner discovered that the 100 bucks is fake. You can th ... 2 m. V; y4 b6 C. g% c" |" B公仔箱論壇( J- ~1 i) k3 \8 b2 ?
5.39.217.76 |9 C* e2 w) x
1) very good, it the 100 bucks is real, your answer is correct, but it is fake, so your answer is wrong
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* k; g2 B3 {# E& N5 t/ u# ]5.39.217.76think 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.tvb now,tvbnow,bttvb/ j l" M0 y" k H ~: d! `* R
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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. |