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标题: ps1 17 19 [打印本页]

作者: mnmicy 时间: 2014-2-9 03:18
标题: ps1 17 19
In a certain board game, a stack of 48 cards, 8 of which represent shares of stock, are shuffled and then placed face down.  If the first 2 cards selected do not represent shares of stock, what is the probability that the third card selected will represent a share of stock?

(A)  1/8 (B)  1/6 (C)  1/5 (D)  3/23 (E)  4/23

19. 2463-!-item-!-187;#058&002761  For a finite sequence of nonzero numbers, the number of variations in sign is defined as the number of pairs of consecutive terms of the sequence for which the product of the two consecutive terms is negative.  What is the number of variations in sign for the sequence 1, -3, 2, 5, -4, -6 ?

  (A) One (B) Two (C) Three (D) Four (E) Five

大家
帮忙
解释!!! thank you

作者: 俺村谁村长 时间: 2014-2-9 22:18
楼主，语法要多练习哦，
第一题，难点是：, 8 of which represent shares of stock, 因为是“非重要语句”，所以被两个都好分开了，读的时候先跳过，即： a stack of 48 cards， are shuffled and then placed face down（然后再补充进来），即，被拿走两个，还剩46个，问拿到那八个的概率选E
第二题，难点是：the number of variations in sign is defined as the number of pairs of consecutive terms of the sequence for which the product of the two consecutive terms is negative 这个一个定义句，读懂才能做，SC典型分析句，即：
（the number of variations in sign）（is defined as ）（the number of pairs ）（of consecutive terms of the sequence）（ for which the product of the two consecutive terms is negative）中文对应翻译为：（个数。。。。）（被定义为）（一对数的个数）（什么样的一对数呢：连续的序列，即连续的数）（什么样的乘机呢：即连续两个数的乘机为负数）（的定义）
选C

作者: mnmicy 时间: 2014-2-9 23:38

俺村谁村长发表于 2014-2-9 22:18
楼主，语法要多练习哦，
第一题，难点是：, 8 of which represent shares of stock, 因为是“非重要语句” ...

万分感谢！

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