Can you help please? Ill give a like!

A mailorder computer business has six telephone lines. Let X denote the number of lines in use at a specied time. Suppose the pmf of X is as given in the accompanying table. X l 0 l 2 3 4 5 6 .000 l0.10 0.18 0.20 0.22 0.20 0.06 0.04 Calculate the cdf Rx). x I o 1 2 3 4 5 6 F(X) l Graph the cdf F{x). Fun Fun Rx] 0 Use the graph to calculate the probabilities of the events given below. (a) {at most three lines are in use} (b) {fewer than three lines are in use}