InterviewSolution
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A bag contains 6 red, 4 white and 8 blue balls. If three balls are drawn at random, find the probability that:(i) one is red and two are white(ii) two are blue and one is red(iii) one is red |
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Answer» Given: A bag containing 6 red, 4 white and 8 blue balls. By using the formula, P (E) = favourable outcomes / total possible outcomes Two balls are drawn at random. Total possible outcomes are 18C3 n (S) = 816 (i) Let E be the event of getting one red and two white balls E = {(W) (W) (R)} n (E) = 6C14C2 = 36 P (E) = n (E) / n (S) = 36 / 816 = 3/68 (ii) Let E be the event of getting two blue and one red E = {(B) (B) (R)} n (E) = 8C26C1 = 168 P (E) = n (E) / n (S) = 168 / 816 = 7/34 (iii) Let E be the event that one of the balls must be red E = {(R) (B) (B)} or {(R) (W) (W)} or {(R) (B) (W)} n (E) = 6C14C18C1 + 6C14C2 + 6C18C2 = 396 P (E) = n (E) / n (S) = 396 / 816 = 33/68 |
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