twinhead

辛苦tongxun了~~~

tongxun

你也不容易啊！努力吧！

zhouxh

What a wonderful job!

Many thanks~~~

hahabear

“ 25、 8 台TV， 6 彩色 and 2 黑白, chose two of them, at least one of the two is 黑白的概率 -------------------------------- 13/28”

MY ANSWER IS C(6,1) * C(2,1) / C(8,2) = 3/7
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"28、有图，一个温度计，从上到下的刻度分别为Y，X，0，Z。X在0上的两个刻度处，Y在0上的四个刻度处，Z在0下的一个刻度处。温度计指示的恰在X与Y的正中央，问刻度为多少？
（1）Y-X=40
（2）X+Z=20 "

It is my question that are the scales on the thermometer even?刻度匀称吗？
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N的立方根为3，根号N^4 = ？

3^2 = 9吧
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18、一路程400KM，一人顺风350km/h，回程时逆风250km/h, 求全程平均速度的近似直
A。280 B。290 C。3** D3** E4**
A 注意是近似值

是 B.290.    800 / (400/350 + 400/250)
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hahabear

N的立方根为3，根号N^4 = ？

3^2 = 9吧

I am wrong, 27^2 = 3^6

tongxun

hahabear:
25、 8 台TV， 6 彩色 and 2 黑白, chose two of them, at least one of the two is 黑白的概率 -------------------------------- 13/28
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The correct solution is:  (C2,2 +c6,1 * c2,1)/c8,2 =(1+12)/28=13/28
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28. because there is a picture in the question, and the author 's answer is this one, I think the scale maybe even.
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18. yes, you are right.

andrewcan

I still do not understand the following well, would any one insttruct? Many thanks!


.A,B,C三组各10个人，D组20人，前三组各取一人，D组取2人，完成一个task，问总共能完成多少种task
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小于1000的正整数中 能被11,19 或两者整除的偶数的个数? (JJ)

唯一一道花了我3分钟以上的题：有一绳放一圆桌上，绳两边都在圆上，the string is in a line and on the top of the center of the roundtable, 圆面积9pi/4，求绳长：(1)3/2, (2).12/5, (3)3, (4)4?, (5)5? 终于认定是道白痴题，选了（3）

tongxun

1、我的想法是：A、B、C、D中按题目的要求抽取人数，能组成多少个不同的小组。
2、能整除11、19、11*19的偶数最小的分别是：11*2、19*2、11*19*2，用998分别除以这3个数，998/（11*2）+998/（19*2） -998/（11*19*2），其中只取整数商。
3、绳子就是直径啊。

cook

Tongxun:

Would you please remark the new answer- the correct one - on different color so that we can look back to review and meanwhile, be warned such error.

Thanks!

tongxun

No probelm！