Question

If the first child of a couple is a boy.Find the
probablity that the second child being a boy.

Answer 1

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& \normalsize \text{ If the first child of a couple is a boy.Find the }\hspace{.33em}\\~\\
& \normalsize \text{probablity that the second child being a boy.}\hspace{.33em}\\~\\
\end{align}}\)

Answer 2

lol

Answer 3

Depending on one's interpretation of probability, the answer is either 1/2 or 1/3.

Answer 4

0? cause in a couple there is 1 girl and 1 boy if i remmeber correctly

Answer 5

hahaha

Answer 6

i think this type of question would not account for past results...

Answer 7

unless your a baby predictor

Answer 8

Read this: http://mathforum.org/dr.math/faq/faq.boygirl.choose.html

Answer 9

similar problem :

If you rolled a coin two times and if you saw HEAD first time, whats the probabiltiy that you see a HEAD on second roll too ?

Answer 10

hahah gane, i'm bad at prob, but i would say 0

Answer 11

@ganeshie8 What do you think the answer should be? 1/2?

Answer 12

is that called mutually exclusive? i forgot

Answer 13

1/2

Answer 14

it can be 1/2 as well

Answer 15

what if you got con-joined twins one a female and the other a male

Answer 16

if thats ever possible

Answer 17

Yes, it has to be 1/2 if it is an unbiased coin; the coin has no memory, it wont remember the previous roll and decide itself to roll on a different face the next time

Answer 18

1/3 (;

Answer 19

That's what I think too. However, this problem is a lot like the Monty Hall Problem, and given that one child is a boy, we eliminate the GG case, which leaves us with BG, GB, BB. That sounds like 1/3.

Answer 20

But again, it should be 1/2.

Answer 21

It is from independent event problem

Answer 22

hmm bg=gb it is not said that the order is needed

i would say 1/2 or 0

Answer 23

female gametes-->XX

male gametes --->XY

when u fuse u get either ----> XX or XY

so it will be 1/2

Answer 24

The probability would be different only if the experiment had already taken place, I think. Then, we can use Bayee inference and use conditional probability..

Answer 25

If the second coin is not rolled yet, then the probability of seeing HEAD on it is 1/2; this much is non negotiable.

Answer 26

On the other hand, if you have rolled the coins and had the results already, then the sample space is :

{HH, HT, TH, TT}

the probability would be 1/3; but clearly, in the main question the baby was not born yet, so the probabiblity for our main question should be 1/2.

Answer 27

Ohhh, so it's about an unborn baby.

Answer 28

Then definitely 1/2.

Answer 29

**
On the other hand, if you have rolled the coins and had the results already, then the sample space is :

{HH, HT, TH, TT}

If somebody tells you that one coin is H, the probability for other coin to be H would be 1/3; but clearly, in the main question the baby was not born yet, so the probabiblity for our main question should be 1/2.

Answer 30

If we're differentiating between the elder and the younger child, then 1/2 is surely the answer.

Answer 31

(;

Answer 32

\(\Huge\color{black}{☺☻☺☻☺☻☺☻☺☻}\)