标题: 问两道老prep的ds题。。。 [打印本页] 作者: lanessay 时间: 2010-3-2 14:22 标题: 问两道老prep的ds题。。。 1.Store S sold a total of 90 copies of a certain book during the seven days of last week, and it sold different numbers of copies on any two of the days.If for the seven days Store S sold the greatest number of copies on Saturday and the second greatest number of copies on Friday, did Store S sell more than 11 copies on Friday? (1)Last week Store S sold 8 copies of the book on Thursday. (2)Last week Store S sold 38 copies of the book on Saturday. 答案选的B
2.If a wire 27 meters long is cut into three pieces of three different lengths, what is the length of the longest piece? (1)The length of the longest piece is twice the length of the shortest piece. (2)The sum of the lengths of the two shorter pieces is 15 meters. 答案选的B，可我觉得是D。。。望NN解答！作者: lanessay 时间: 2010-3-2 15:07
自己顶一下。。。作者: 切尔西 时间: 2010-3-2 15:18
第一题：可以根据条件2种，星期六买了38份，先假定周五卖了11份，剩余还有41份其余的5天来卖，因为每天卖的数量不一样，所以剩下五天卖的最大值是10，9，8，7，6，加起来综合是40，比41小，所以肯定有一天卖了11份，而周五又是一周中卖的第二多的一天，所以一定大于11