Q. 215.0( 2 Votes )

Two balls are drawn at random with replacement from a box containing 10 black and 8 red balls. Find the probability that (i) both balls are red, (ii) first balls is black and second is red, (iii) one of them is black and other is red.

Answer :

Given an urn contains 10 black balls and 8 red balls


Probability of getting red ball=


Probability of getting black ball=


(i) both balls are red


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



(ii) first balls is black and second is red


P(first balls is black and second is red)=P(B)*P(R)


(iv) one of them is black and other is red.


P(one of them is black and other is red)=P(B)P(R)+P(R)P(B)



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