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工作学习 / English / 有大虾知道这道题目是怎么解出来的吗？为什么要乘2？
五辆车，朝相同的方向停，3蓝，1黄1红，其中3蓝不可分辨，问有多少种停法？（old JJ,2*p(5,5)/P(3,3) =40）
-merymaid(merymaid);
2002-10-9
(#788378@0)
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The 2 is coming from you can either face out or face in by ALL cars.. Like ALL cars can be head in or ALL cars can be tail in.
-jeffrey815(Smartiecat);
2002-10-9
(#788405@0)
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看不懂题目，兰色一定要分开？
-oceandeep(北极熊® Zzz Zzz);
2002-10-9
(#788408@0)
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All blue cars are identical.
-jeffrey815(Smartiecat);
2002-10-9
(#788415@0)
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5*4*2
-oceandeep(北极熊® Zzz Zzz);
2002-10-9
(#788418@0)
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先红的选，有5种可能，再黄的选4种可能，然后红色和黄色可以互换所以是5*4*2
-oceandeep(北极熊® Zzz Zzz);
2002-10-9
(#788421@0)
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no... If you can interchange red and yellow, that means you are restricting the first and the second choice, so you can't use 5 * 4.
-jeffrey815(Smartiecat);
2002-10-9
(#788426@0)
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So it's 2*5!/3!
-jeffrey815(Smartiecat);
2002-10-9
(#788409@0)
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乘2的原因是不是因为可以头进或者尾进呀？如果不是请解释清楚些了。我怎么老是算出来20呀？
-merymaid(merymaid);
2002-10-9
(#788441@0)
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Can you state the English original of the problem?
-jeffrey815(Smartiecat);
2002-10-9
(#788450@0)
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就是的, 你的理解正确.乘2的原因是因为可以头进或者尾进.
-flyingpipi(flying_pipi);
2002-10-9
(#788662@0)
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Ask me any stat or probability questions if you want. it's my major.
-jeffrey815(Smartiecat);
2002-10-9
(#789394@0)
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how about parallel parking? how about diagonal parking lots? so the answer is ∞
-noexit(书中自有▲省油灯);
2002-10-9
(#788439@0)
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应该是20啊，其实就是5个位置中选2个位置给黄车红车。p(2,5)=20
-stills(最后的疯狂);
2002-10-9
(#788466@0)
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就你提供的条件看，这道题是这么解的。估计是jj条件不全。怎么在准备gre啊。
-stills(最后的疯狂);
2002-10-9
(#788476@0)