Mathematics Part-II

Book: Mathematics Part-II

Chapter: 13. Probability

Subject: Maths - Class 12th

Q. No. 10 of Exercise 13.5

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A person buys a lottery ticket in 50 lotteries, in each of which his chance of winning a prize is 1/100. What is the probability that he will win a prize

(a) At least once

(b) Exactly once

(c) At least twice?

(a) In this question, let X represents the number of prizes winning in 50 lotteries and the trials are Bernoulli trials

Here clearly, we have X is a binomial distribution where n = 50 and


Hence, probability of winning in lottery atleast once

= 1 – P (X <1)

= 1 – P (X = 0)

(b) Probability of winning in lottery exactly once

(c) Probability of winning in lottery atleast twice

= 1 – P (X < 2)



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