2008-9-7换题后 数学鸡精 汇总、讨论（1-50题）

arcsun

以下是引用daruiza在2008-9-8 2:03:00的发言：

28.
  一道PS：

一个数等于2的51次方，另一个数等于2的x次方乘以3的立方，二者有相同个数的正整数因子，问x等于多少？

答案是12，我算的，基本确定

请问这道题的思路是什么，我怎么没算出来

2^51 除了1之外有51个因子

2^x X 3^3的因子除了1因该有C_x¹C₃¹+C_x¹+C₃¹  ====>C_x¹=12

个人理解请指正。

princeofqin

以下是引用daruiza在2008-9-8 2:03:00的发言：

28.
  一道PS：

一个数等于2的51次方，另一个数等于2的x次方乘以3的立方，二者有相同个数的正整数因子，问x等于多少？

答案是12，我算的，基本确定

请问这道题的思路是什么，我怎么没算出来12

自己JJ自己回答：

2的51次方有52个正数因子（含1和自身）

3的立方有4个因子：1  3  9  27

2的x次方排除1外有x个正数因子

二者结合，则有4x个正数因子（最简单的组合），即有：4x+4=52，因此x=12

梵尘

谢谢princeofqin来指导！

也欢迎更多XDJM一起来讨论，

帮助大家，快乐自己！

linchen014

谢谢楼主~~太感恩了~~~

lazzycat_wxh

以下是引用梵尘在2008-9-7 23:50:00的发言：

710机经，分数不易，考前几天神经恍惚

http://forum.chasedream.com/dispbbs.asp?boardID=22&ID=345357&page=1

1. PS:Space diangonal is a diagonal connecting two vertices on different planes. If 边长 of the cube is 5. What is the diagonal?

2. PS:A shop sells tshirt in white and red with two sizes: medium and large......How many medium tshirt does the shop sell?

3. PS:ABC is a triangle. D is the midpoint of BC. E is the midpoint of AC while F is midpoint of EC. If area of triangle ABC is 24. What is the area for triangle DEF? 8

4. A class of 35 students take part in an test. How many students are below the average score?

1. The average score is 86

2. The median score is 86

5.由一个求median的题

6. People who earn more than 40000 for their salaries should submit 6% of 40000 and x% for the part exceeding 40000. If a people earn 某个数 and submit 某个数, what is X? 数忘记了，但答案是5.

7. [a] is the smallest integer with a value larger than a. What is [a]-?

1. a-b=1.5

2. 忘了   

8. a is integer. *a=a-1 if a is even while a*=a+1 if a is odd. Which of the following number is odd?

9. A financial investment club has ** members with investment either in bond or in stocks. ** don't invest in either of them. ** invest in stock. ** invest in bond. hnow many people invest in both?

10. How many numbers between 9 to 100, inclusive, can be divided exactly by both 3 and 7?

第三题答案是3吧？

EVO10代

Lots of Thanks!

我同意楼上的TRIANGLE底变成1/4,高变成1/2,总面积应为1/8

[此贴子已经被作者于2008-9-8 4:15:56编辑过]

tottl925

感谢楼主对华夏儿女的贡献，赞rp！！

jmbnzhu

thank you

abcabc

    

11.记得比较清楚地一道DS是

问X^4+Y^4>Z^4？

条件1：X^2+Y^2>Z^2

条件2：X+Y>Z

不知道是脑子木了还是咋回事，折腾半天没想出来，也没想好有什么反例，反正C或者E瞎选了一个

数学一开始太轻视了，Pace没有掌握好，第一道最傻的题花了4分钟。。。悔之晚矣= =b

is E ??

dianecarton

再次感谢

[此贴子已经被作者于2008-9-11 11:01:41编辑过]