A mail order company business has six telephone lines Let X

Last updated: 3/11/2023

A mail order company business has six telephone lines Let X denote the number of lines in use at a specified time Suppose the pmf of X is as given in the accompanying table 0 1 2 3 4 5 6 p x 0 11 0 15 0 20 0 25 0 19 0 09 0 01 X Calculate the probability of each of the following events a at most three lines are in use b fewer than three lines are in use c at least three lines are in use d between two and five lines inclusive are in use e between two and four lines inclusive are not in use f at least four lines are not in use