City of Ann Arbor wishes to form a Green Club, a group of people devoted to green technology. The club is open to all, and enrollment is done on rst-come- rst-serve basis. The enrollment stops when there are exactly 5 people who are born on January 1 in the club. Assume that there are always enough people in Ann Arbor who wish to join the club. Let X denote the size of the club. Find the expected value of X. (Assume that there are no leap years).

1820

Step-by-step explanation:

X the size of the club will follow negative binomial distribution with probability of success p and number of failures r

p = 364/365, r = 5

hence E[x] = pr/(1-p) = 364/365 x 5 /(1/365) = 1820

proofs involving isosceles triangles often require special consideration because an isosceles triangle has several distinct properties that do not apply to normal triangles.(more about triangle types) therefore, when you are trying to prove that two triangles are congruent, and one or both triangles, are isosceles you have a few theorems that you can use to make your life easier.

step-by-step explanation:

an isosceles triangle has two congruent sides and two congruent angles. the congruent angles are called the base angles and the other angle is known as the vertex angle. ∠bac and ∠bca are the base angles of the triangle picture on the left. the vertex angle is ∠abc