ChaseDream
搜索
返回列表 发新帖
查看: 1524|回复: 2

TT_GWD_25-11,6

[复制链接]
发表于 2006-10-23 00:27:00 | 显示全部楼层

TT_GWD_25-11,6

 

I searched the old discussions, but I haven't found the relative one.

Q11

Of the three-digit positive integers that have no digits equal

to zero, how many have two digits that are equal to each

other and the remaining digit different from the other two?

A.     24

B.     36

C.     72

D.     144

E.      216 (E)

Q6

A string of 10 lightbulbs is wired in such a way that if

any individual lightbulb fails, the entire string fails. If for

each individual lightbulb the probability of failing during

time period T id 0.06, what is the probability that the

string of lightbulbs will fail during time period T?

 

   A.0.06

   B.(0.06)^10

   C.1-(0.06)^10

   D.(0.94)^10

   E.1-(0.94)^10(E)

Q11, I guess the answer is E, but I got C91*c91*3=243, but there are some numbers repeated, so they have to be subtracted, but I don' t know why.

And Q6, I thought is (0.06)^10

Can sb. help? I will have my test in 7 days.

It's so bad, my computer cannot write in Chinese.

发表于 2006-10-23 11:20:00 | 显示全部楼层

Q6

串联的灯泡任何一个的故障都会导致整串的failure,所以只要排除全部都完好的情况就是可能出现故障的概率了.

所以 1-(1-0.6)^10

发表于 2006-10-23 14:44:00 | 显示全部楼层

Q11

如果相同的数字是1,另外的数字有8种可能

这两个1跟另外一个数字随机排列,有3种可能,那么一共有3*8种可能

想同的数字可以是1到9,9  种可能

那么一共就是9*3*8=216种可能

您需要登录后才可以回帖 登录 | 立即注册

Mark一下! 看一下! 顶楼主! 感谢分享! 快速回复:

手机版|ChaseDream|GMT+8, 2024-3-29 22:21
京公网安备11010202008513号 京ICP证101109号 京ICP备12012021号

ChaseDream 论坛

© 2003-2023 ChaseDream.com. All Rights Reserved.

返回顶部