It Is Known That 70% of the Customers in a Sporting

Short Answer

It is known that 70% of the customers in a sporting goods store purchase a pair of running shoes. A random sample of 25 customers is selected. Assume that customers' purchases are made independently, and let x represent number of customers who purchase running shoes.
What is the probability that exactly 18 customers purchase running shoes?
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What is the probability that no more than 19 customers purchase running shoes?
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What is the probability that at least 17 customers purchase running shoes?
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What is the probability that between 17 and 21 customers, inclusively, purchase running shoes?
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