A person has 3 children with at least one boy. Find the probablitiy of having atleast 2 boys among the children ?
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P(at least 2 boys|1boy)
\(\large \color{black}{\begin{align} & \normalsize \text{A person has 3 children with at least one boy.} \hspace{.33em}\\~\\ & \normalsize \text{Find the probablitiy of having atleast 2 boys } \hspace{.33em}\\~\\ & \normalsize \text{among the children ?} \hspace{.33em}\\~\\ \end{align}}\)
how to solve this P(at least 2 boys|1boy) ?
you can click edit and put it in the blue part
thnks for suggestion
P(at least 2 boys | at least 1boy) = P(at least 2 boys and at least 1 boy)/P(at least one boy) P(at least 2 boys)/P(at least one boy)
is this like bayes therem
no just conditional probability Bayes is a little different
P(at least 2 boys)/P(at least one boy)=(1/3+1/3)/(3/3)
not quite... P(At least 2 boys) = P(2 boys) + P(3 boys) P(at least 1 boy) = 1-P(no boys)
=(1/3+1/3)/(1-0/3) =?
P(no boys) = P(all girls) how many children does the couple have? 3. => P(all girls) = P(GGG) = (1/2)(1/2)(1/2) = 1/8
final answer=(2/3)/(1/8)=1/12
|dw:1444505252205:dw|
the area of the smallest circle divded by the bigger circle
no P(At least 2 boys) = P(2 boys) + P(3 boys) P(3 boys) = P(3 girls) = 1/8 P(2 boys) = 3C2 * (1/8) = 3/8 P(At least 2 boys) = 1/2
Prob of atleast 2 boys = prob of atleast 1 boy - prob of only 1 boy prob of @2boys/prob of @ 1 boy = (prob of atleast 1 boy - prob of only 1 boy)/prob of @ 1 boy = 1- prob_of_1_boy/prob of @ 1 boy = 1- prob of 1 boy/(1-prob of no boys)
P(at least 2 boys)/P(at least one boy)=(1/2)/(1/8)=1/4 , is it
|dw:1444505457548:dw|
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