Question

From experience, the manager of Kramer's Book Mart knows that 30% of the people who are browsing in the store will make a purchase. What is the probability that among ten people who are browsing in the store, at least seven will make a purchase?

Answer 1

Answer:

Step-by-step explanation:

Given that:

• prob of purchase = 0.3

• prob of no purchase = 0.7

prob of at least 7 from 10 will make purchase

= prob(7will buy) + prob(8 will buy) + ..+ prob(10 will buy)

= C(10,7) $0.3^{7}$ $0.7^{3}$ + C(10,8) $0.3^{8}$ $0.7^{2}$ + C(10,9) $0.3^{9} 0.7^{1}$ + C(10,10)$0.3^{10}$

= 0.0105

So the probability that among ten people who are browsing in the store, at least seven will make a purchase is: 0.0105