PLS 看看,对机警几题的疑惑(2)

8．S^2+R^2的square roots 是整数吗？
（1） S+R=9
（2） S〈R
//////我认为选A 对吗？？
9． N*=N^2+1,K*=?
(1) K^2除以4余1
(2) K*大于18小于等于36
//////我认为选C
10． 4 entrees, one of them is “fish”, 15 people, Q: is there at least 1 person order “fish”?
(1)there are no any entrees ordered by more than 5 people
(2)one dish less than 4 people ordered …(something like this)…
### (C) …(SURE)
///////我认为选E，NOT ……MORE THAN 5则可以5，5，5而且0〈4
这样想对吗
11．DS: 两班学生考试, A and B, the scores show that means of A and B are 84 and 78, respectively, Media of A and B are 75 and 82, respectively. Does the mean of A+B greater than the media of A+B?
A) I forgot… B) the number of students in A and B is 43 and 37.
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E
条件B）：平均值=81。A、B两班和起来，共80人，中数为40+41的和。
根据题目，A班中有22人多于75分，B班有19人多于82分。即41人多于75分，但不能确定是否多于80分。
/////宝典中有一道很相似的题：
DS: 两班学生考试, A and B, the scores show that means of A and B are 82 and 74, respectively, Media of A and B are 80 and 78, respectively. Does the mean of A+B greater than the media of A+B?
A) A+B=77  B) the number of students in A and B is 37 and 40
答案是B
这是为什么？？？

12. DS
上层架放了45个咚咚，下层架放了44各咚咚。上层的45个每个的重量都小于下层44个的任何一个。问共89个的median？
1.上层中最重的重量是8。
2.下层中最轻的重量是8.1。
答案：A
///////并不能保证上层中的第45个是最重的一个呀？？？？
13．The number of boys in a class and the number of the totle of boys and girls who take the course of biology is shown in the form blew, How many is all the boys and girls in the class.
表格 take biology not take biology    totle
----------------------------------------------------------
boy    M          N             28
----------------------------------------------------------
girl    A          B                X
----------------------------------------------------------
totle 36             Y
1. There are 3 boys who do not take biology
2. The girls in the class is twice as many as the totle of boys and girls who do not take biology
-------------------------------------
C
==================================
////// 我认为选B
M+N=28    A+B=X M+A=36 N+B=Y 36+Y=28+X  求28+X=？
1） N=3
2） X=2（N+B）=2Y=2（28-36+X）= —16+2X
X=16
28+X=44