Q. 224.5( 2 Votes )

An urn contains 4 red and 7 black balls. Two balls are drawn at random with replacement. Find the probability of getting (i) 2 red balls, (ii) 2 black balls, (iii) one red and one black ball.

Answer :

Given an urn contains 4 red and 7 black balls


Probability of getting red ball=


Probability of getting black ball=


(i) two red balls


P(getting two getting red balls)=P(R)*P(R)



(ii) two black balls


P(getting two blue balls)=P(B)*P(B)



(iii) first red and second black ball.


P( getting one red and one black ball)=P(R)*P(B)+P(B)*P(R)



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