Question 574069
Let X = the number belonging to an HMO
a. P(X = 5) = {{{(matrix( 2, 1, 20, 5))*(0.2^5)*(0.8^15)}}}
            = 0.17456

b. {{{P(X>=1) = 1 - P(X=0)}}}
              = {{{1 - (matrix( 2, 1, 20, 0))*(0.2^0)*(0.8^20)}}}
              = 0.98847