数学M/S Paper 2讨论专区

peaceboy

回复 340# hongji


    可以
这个好像是math T的syllabus

hongji

回复 341# peaceboy


    那么stpm 考试就不能看log book哦？

peaceboy

回复 342# hongji


    可以~！

whyyie

你们觉得Paper 2 哪本书好用?

hongji

我不明白probability的问题很多不会做
下星期就考了

1)In how many ways can odd numbers greater than 4000 be formed from the digits 1,2,4 and 8 if the digts can only be used once.

4!=24>>>n(s)  ?



2)a teacher , 2 girls and 3 boys are to be seated in a line.
  find the number of ways the six people can be arranged if the teacher

a)can sit at any place 这个我会  6！=720
b)sits between 2 girl这题可以教我怎样看做吗。。

hongji

bag A contains 5 red cubes and 3 blue cubes while bag B contains 4 red cubes and 7 blue cubes .A cubes is selected at random from bag A and placed in bag B , and a cube is then selected randomly from bag B.
Events B1 , M1 ,B2 ,M2 are defined as follows :
B1 : the cube placed into bag B is blue
M1 :the cube placed into bag B is red
B2 :the cube placed into bag B is blue
M2 :the cube placed into bag B is red
Find
(a) P(B1)
(b)P(B2 l M1)

peaceboy

回复 345# hongji


    1)In how many ways can odd numbers greater than 4000 be formed from the digits 1,2,4 and 8 if the digts can only be used once.

1*2！*1 + 1*2！*1


2)a teacher , 2 girls and 3 boys are to be seated in a line.
  find the number of ways the six people can be arranged if the teacher

a)can sit at any place 这个我会  6！=720

b)sits between 2 girl这题可以教我怎样看做吗。。
2！*4!

peaceboy

回复 346# hongji


    bag A contains 5 red cubes and 3 blue cubes while bag B contains 4 red cubes and 7 blue cubes .A cubes is selected at random from bag A and placed in bag B , and a cube is then selected randomly from bag B.
Events B1 , M1 ,B2 ,M2 are defined as follows :
B1 : the cube placed into bag B is blue
M1 :the cube placed into bag B is red
B2 :the cube placed into bag B is blue
M2 :the cube placed into bag B is red
Find
(a) P(B1)
(b)P(B2 l M1)

问题有密友打错？

hongji

回复  hongji


    bag A contains 5 red cubes and 3 blue cubes while bag B contains 4 red cubes  ...
peaceboy 发表于 3-3-2011 10:37 PM

    ya,打错了><
bag A contains 5 red cubes and 3 blue cubes while bag B contains 4 red cubes and 7 blue cubes .A cubes is selected at random from bag A and placed in bag B , and a cube is then selected randomly from bag B.
Events B1 , M1 ,B2 ,M2 are defined as follows :
B1 : the cube placed into bag B is blue
M1 :the cube placed into bag B is red
B2 :the cube selected form bag B is blue
M2 :the cube selected form bag B is red
Find
(a) P(B1)
(b)P(B2 l M1)

hongji

回复  hongji


    1)In how many ways can odd numbers greater than 4000 be formed from the digit ...
peaceboy 发表于 3-3-2011 10:35 PM

    2)a teacher , 2 girls and 3 boys are to be seated in a line.
  find the number of ways the six people can be arranged if the teacher

a)can sit at any place 这个我会  6！=720

b)sits between 2 girl这题可以教我怎样看做吗。。
2！*4!if c)sits between 2 boys?

peaceboy

回复 349# hongji


    bag A contains 5 red cubes and 3 blue cubes while bag B contains 4 red cubes and 7 blue cubes .A cubes is selected at random from bag A and placed in bag B , and a cube is then selected randomly from bag B.
Events B1 , M1 ,B2 ,M2 are defined as follows :
B1 : the cube placed into bag B is blue
M1 :the cube placed into bag B is red
B2 :the cube selected form bag B is blue
M2 :the cube selected form bag B is red
Find
(a) P(B1)

3/8

(b)P(B2 l M1)

P(M1) = 5/8
P(B2 n M1) = 5/8*7/12

P(B2 l M1) = ( 5/8*7/12)/(5/8)
                =7/12

peaceboy

回复 350# hongji


    c)sits between 2 boys?

4*3*4!

hongji

回复  hongji


    c)sits between 2 boys?

4*3*4!
peaceboy 发表于 4-3-2011 10:18 PM

    怎样看的？

peaceboy

回复 353# hongji

不好意思做太快看错

    老师的左边可以放3个男的，右边剩下2个
这样的话老师和两个男的固定一组
剩下的2女1男和老师那一组又可以做成4!

所以答案是 3*2*4!

whyyie

Minute

The registration no. of vehicles in a certain country use digits 1 to 999.If a visitor has just entered the country, what is the probability that the first car he see has at least 2 identical digits?

peaceboy

回复 356# Minute


    The registration no. of vehicles in a certain country use digits 1 to 999.If a visitor has just entered the country, what is the probability that the first car he see has at least 2 identical digits?

orz还真的没有人要解

from 1 - 99 = 9
digit from 100 - 999 that have 3 different number = 9*9*8
                                                                     = 648
900- 648 = 252

total = 252+9
        = 261

數學神童

在 network planning, 我们怎么知道几时用 total float, free float 或independent float??

hongji

今天的考试有一题不知道对不对我想看你们的答案

the number of computers , X , sold in a day by a computer shop has the probability distribution as follows:



P(X=x)={ 0.25-0.05x,x=0,1,2,3;
                           a,x=4,5
                              0,otherwise


a)determine the value of the constant a

b)find the probability that 3 or 4 computers have been sold in a day

peaceboy

回复 359# hongji


    0.25-0.05(0)+0.25-0.05(1)+0.25-0.05(2)+0.25-0.05(3) +a +a =1
0.7+2a =1
a= 0.15

P(2 u 3) = P(2) + P(3)
            = 0.25-0.05(2)+0.25-0.05(3)
            = 0.25