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Question
In a certain lottery 10,000 tickets are sold and ten equal prizes are awarded. What is the probability of not getting a prize if you buy 10 tickets.
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Solution
Number of tickets that are not getting a prize
= 10000 – 10
= 9990
∵ Total number of tickets = 10000
Similarly, number of ways to get 10 tickets not getting prizes out of 9990 = `""^9990C_10`
number of ways to get 10 tickets out of 10000 = `""^10000C_10`
Hence, probability of not getting prizes with 10 tickets
= `(""^9990C_10)/(""^10000C_10)`.
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