作者LPH66 (圬琐)
看板puzzle
标题[中译] Puzzleup 2012 (16) Faulty Product
时间Wed Nov 7 23:46:23 2012
题目网址:
http://www.puzzleup.com/2012/?home
http://www.puzzleup.com/2012/puzzle/?257
答题时限: 11月８日７ＰＭ－比赛结束（约１２月１２日）
加分时限: 11月８日７ＰＭ－11月13日６：５９ＰＭ
答对可得基本分１００分。答案可上传５次，每改１次答案从基本分扣２０分。
另有两种加分： １. 加分时限内答对。例：第Ｎ天答对，可加（６－Ｎ）分。
２. 题目越困难，加分越多。例：这题有ｎ％的人答错，答对者加ｎ分。
◆Faulty Product
In a factory every 5 products out of 100 are faulty. Samples from a randomly
selected product are sent to two different labs for testing. Labs have an
accuracy of 75%, and 90% respectively. If both of the labs report the product
is faulty, what is the probability that it really is?
Note: The probability of a lab reporting a faulty product as faulty and a
faultless product as faultless are both equal to the accuracy of the lab.
Enter your answer as a simplified fraction. Example:12/23
一个工厂里每一百个成品就有五个不良。
现随机抽样成品送给两个不同的实验室测试。两个实验室的准确率分别是 75% 及 90%。
若两实验室皆回报不良，则它真的不良的机率是？
注：实验室回报不良品为不良品的机率及回报良品为良品的机率皆为其准确率。
将答案以最简分数表示，例如 12/23。
--
基本分来了 (茶)
--
LPH [acronym]
= Let Program Heal us
-- New Uncyclopedian Dictionary, Minmei Publishing Co.
--
※ 发信站: 批踢踢实业坊(ptt.cc)
◆ From: 180.218.108.125
※ 编辑: LPH66 来自: 180.218.108.125 (11/07 23:50)
1F：推 Django:真的蛮基本的0.0 11/08 00:08
2F：推 newacc:这感觉像是某种高中数学竞赛的题目XD 11/08 01:07
3F：推 walkwall:这不是Puzzleup 这不是Puzzleup (遮脸) 11/08 03:30
※ 编辑: LPH66 来自: 180.218.108.125 (11/08 09:00)
4F：推 Django:比较像课本练习题吧 XD 数学竞赛出这个有点... 11/08 15:23
5F：推 lollygagger:75%准度实在不高，95%的良品有1/4会验成不良呢 11/08 18:41