probablity

Question

Answer 1

question is bit tricky in that line :

       "one of them is found to be good "  --> it does not tell which one good 1st one or 2nd one . so total combination possible in which one is found to be good ={good ,good} ,{bad,good} ,{good,bad}

out of this question asked for other is also good . it means -{good,good} combination .  so answer should be = 1/3

Comments

Use Bayes theorem(ans=1/3). What you done is rather considered positions.

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now check @sushanth

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Yes, right.

Answer 2

answer is this exaplain ?

Comments

Consider using Bayes theorem.

P(other egg also good/ one egg is good)

= P(both eggs are good) / P(one egg is good)

 

Now,

P(both eggs are good) = 4C2 / 7C2

P(one egg is good) = P(one egg is good)*P(one egg is bad) + P(both eggs are good)

                            = (4C1 * 3C1)/(7C2)  +  (4C2)/(7C2)

That gives 1/3.

Answer 3

selecting any two egg=⁷C₂

now selecting all two rotten egg=³C₂

at least one egg is good=⁷C₂-³C₂=18

now another egg also has to be good ⁴C₂=6

so prob=6/18=1/3

Comments

it is too complicated ..plz provide me the approach why can be simply did as answered by kaushik above ? as these kind of question have every time different approach ?