Q19 of 28 Page 16

A bag contains 8 red and 5 white balls. Three balls are drawn at random. Find the probability that:

(i) All the three balls are white


(ii) All the three balls are red


(iii) One ball is red and two balls are white

given: bag which contains 8 red and 5 white balls


We know,



total number of ways of drawing three balls at random is 13C3.


therefore n(S)=286


(i) let E be the event of getting all white balls


E= {(W) (W) (W)}


n(E)= 5C3





=10





(ii) let E be the event of getting all red balls


E= {(R) (R) (R)}


n(E)= 8C3





=56





(iii) let E be the event of getting one red and two white balls


n(E)= 8C1× 5C2





=80





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