DSE 2009 Q38

[Khagesh]

Wats d ans for dis Q:

A family has 2 children, 1 of them is daughter. Wat is d probab that oder child is also a daughter?

I thnk it shld b 1/2 bt ans key says 1/3

[Chinni18]

Khagesh: The family can have kids as follows: BB, BG, GB, GG
Given that one is a girl, you can eliminate BB
That leaves 3 options
Hence 1/3

[Khagesh]

Umm kk, bt shldnt it be dat it's 1/2 i mean, d logic ur giving is of combination possible. I mean i thnk d child's sex is independent of his siblings

[Chinni18]

Okay look at it this way then:
P(both being daughter| One is daughter)
=P(Both daughters) / P(One is a daughter)
=(1/4)/(3/4)
=1/3

[aditi5000]

A family has 2 children, 1 of them is daughter. Wat is d probab that oder child is also a daughter?

SS={bb,bg,gb,gg}

P(gg|one is a girl) = P(gg intersection one is a girl)/P(one is a girl) = 1/4 / 3/4 = 1/3

[Khagesh]

Aah...kk gots its :D

thnx...didnt thnk of it as condt probab!

Btw dre one more prob pending plz if u can solve dat too guys

[Chinni18]

You're welcome  What problem is that one?

[khagesh.batra]

Same xam 35 Q

A Co. has 100  emps, with 40 men n 60 women. 6 male exec. No. of female exec for gender n rank independence ?? 

On Mon, Jun 18, 2012 at 8:20 PM, Chinni18 [via Discussion forum] <[hidden email]> wrote:

You're welcome  What problem is that one?

---

If you reply to this email, your message will be added to the discussion below:

http://discussion-forum.2150183.n2.nabble.com/DSE-2009-Q38-tp7578090p7578102.html

To unsubscribe from DSE 2009 Q38, click here.
NAML

[Khagesh]

Same xam 35 Q

A Co. has 100  emps, with 40 men n 60 women. 6 male exec. No. of female exec for gender n rank independence ??

[Chinni18]

A Co. has 100  emps, with 40 men n 60 women. 6 male exec. No. of female exec for gender n rank independence ??
Let E be the event EXecutive
M=>Male
F=> Female
Let x be reqd no. of female execs
We need P(E/M) = P(E/F)
=> [(6/100)/(40/100)] = [(X/100)/(60/100)]
x= 360/40 =9

[Khagesh]

Thnxa ton yaar :D
Topper man !! :D :D thnx

[Chinni18]

Hahahaha thanks Khagesh  Glad to be of help! All the best!!

[Khagesh]

Same to same to u ;) :D

btw soon i'll b posting doubts abt Eco based q, plz do solve dem too :)

[Chinni18]

Sure Khagesh, if I am able to solve I will definitely help  

On Mon, Jun 18, 2012 at 8:31 PM, Khagesh [via Discussion forum] <[hidden email]> wrote:

Same to same to u ;) :D

btw soon i'll b posting doubts abt Eco based q, plz do solve dem too :)

---

If you reply to this email, your message will be added to the discussion below:

http://discussion-forum.2150183.n2.nabble.com/DSE-2009-Q38-tp7578090p7578110.html

To unsubscribe from DSE 2009 Q38, click here.
NAML

[Chinni18]

Sure Khagesh, if I am able to solve I will definitely help

[Khagesh]

N dat marked ur 100th post :P

[s]

hey for question 38 , while constructing the sample space why do we consider the order of the child being a B or G? you are treating the events like that of coin tosses..as in nothing has been mentioned like for instance if the older child is daughter or anything like that..its rather silly for me to ask this but do we always treat sums like these by keeping in mind the order?....actually i always get stuck with sums like these so it would be really nice if someone can clarify

[deepak]

I think it's because unlike 2 red balls, 2 sisters can't be considered the same? Just thinkin' aloud

[Chinni18]

Your reasoning is exactly the reason Deepak
S, you can go through these links, this question is actually a very famous problem in probability, called the Boy-girl paradox
Boy_or_Girl_paradox
Boy or girl paradox

[s]

thanks chinni and deepak

i have another question:
a father has 3 children with atleast one boy.the probability that he has 2 boys 1 girl is_______
answer given is 1/3...but shouldnt it be 3/7? the sample space being {BBB,GGG,BGG,BGB,GBB,GGB,GBG,BGG}