一道机经难题加一道GWD DS题求解

pychina

Theater M has 25 rows with 27 seats in each row.  How many of the seats were occupied during a certain show?
(1)   During the show, there was an average (arithmetic mean) of 10 unoccupied seats per row for the front 20 rows.
(2)   During the show, there was an average (arithmetic mean) of 20 unoccupied seats per row for the back 15 rows.

先看看GWD这个吧,答案是E.对于这种题目,思路是什么呢,拿到1,2是算不出来,但怎么能确定是算不出而不是不会算呢.如果要知道how many,我们必须知道什么,难道说只有把2的20改成15unpoccupied seats才可以选C吗.

另一题目jj,x的所有位数的数字之和是170,y是个两位数,X=10^20-Y,问Y=多少?答案说了3个43 46 50还有两个不知道.

这题我的思路是170/9=18...8,即10^19-2 现在是10^20次方,则必然多出个9来,相应的X的倒数两位原来是9+8=17,在多出个9的情况下,新的倒数两位之和应该等于8.即jj给出的答案选项里没有正确答案,正确答案可能是44或者53之类,是不是啊,请教各位

yankevi

http://forum.chasedream.com/dispbbs.asp?boardID=22&ID=296470&page=2

pychina

楼上的祝你11日一战成功,我个人认为,在你这个日期考,一定要把jj好好利用起来,我遇到过一个在你相似日期考的朋友,遇到了4篇阅读jj.再次祝福你

pychina

GWD那题有人解答一下思路吗

yankevi

Theater M has 25 rows with 27 seats in each row.  How many of the seats were occupied during a certain show?
(1)   During the show, there was an average (arithmetic mean) of 10 unoccupied seats per row for the front 20 rows.
(2)   During the show, there was an average (arithmetic mean) of 20 unoccupied seats per row for the back 15 rows.

其实楼主只要把题目意思理解清楚就可以解答了。。

这里说的是一共有25排，每排27个位置，问你一共有多少个位置有人坐？

1，说前面的20排里面，空位的平均值是每排10个。那你只能算出前20排的坐的位置数是20x27-10x20,但是你不知道后面5牌的利用率

2，说后面15排的里面，空位率是10个、每排，你也只能证明是后面25排的坐的位置，前面10排不知道

结合看一下，你只能发现前面20排和后面15排的位重复了10排（因为总共才25排啊）。你不知道重复的位置有多少。。