Question

A real estate agent has 1313 properties that she shows. She feels that there is a 40%40% chance of selling any one property during a week. The chance of selling any one property is independent of selling another property. Compute the probability of selling at least 11 property in one week. Round your answer to four decimal places.

Answer 1

0.0013

Explanation:

The probability of selling a property is 40%, so the probability of not selling it is 60%.

To find the probability of selling at least 11 properties, we can calculate the following cases:

Selling 11:

P(11) = C(13,11) * P(sell)^11 * P(not sell)^2

P(11) = (13! / (11! * 2!)) * 0.4^11 * 0.6^2

P(11) = 13*12/2 * 0.4^11 * 0.6^2 = 0.001178

Selling 12:

P(12) = C(13,12) * P(sell)^12 * P(not sell)^1

P(11) = (13! / (12! * 1!)) * 0.4^12 * 0.6^1

P(11) = 13 * 0.4^12 * 0.6 = 0.000131

Selling 13:

P(13) = C(13,13) * P(sell)^13 * P(not sell)^0

P(11) = 1 * 0.4^13 * 0.6^0

P(11) = 1 * 0.4^13 * 1 = 0.000007

Final probability:

P(at least 11) = P(11) + P(12) + P(13)

P(at least 11) = 0.001178 + 0.000131 + 0.000007 = 0.001316

P(at least 11) = 0.0013