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InterviewSolution
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A die is thrown twice. What is the probability that(i) 5 will not come up either time?(ii) 5 will come up at least once? [Hint: Throwing a die twice and throwing two dice simultaneously are treated as the same experiment] |
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Answer» Outcomes= (1,1),(1,2),(1,3),(1,4),(1,5),(1,6) (2,1)(2,2),(2,3),(2,4),(2,5),(2,6) (3,1),(3,2),(3,3),(3,4),(3,5),(3,6) (4,1),(4,2),(4,3),(4,4),(4,5),(4,6) (5,1),(5,2),(5,3),(5,4),(5,5),(5,6) (6,1),(6,2),(6,3),(6,4),(6,5),(6,6) (i) P(5 will not come up either time) = 25/36 Explanation:- 5 will not come up either time means In the throw no dice gets a number 5 on them so possible outcomes = (1,1),(1,2),(1,3),(1,4),(1,6) (2,1)(2,2),(2,3),(2,4),(2,6) (3,1),(3,2),(3,3),(3,4),(3,6) (4,1),(4,2),(4,3),(4,4),(4,6) (6,1),(6,2),(6,3),(6,4),(6,6) (ii) P(5 will come up at least once) = 11/36 Explanation:- 5 will come up at least once means either of the dice gets a number 5 on them. So possible outcomes are :- (1,5),(2,5),(3,5),(4,5),(6,5) (5,1),(5,2),(5,3),(5,4),(5,5),(5,6) |
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