Can you help please? I'll give a like!

A mailorder compan'yr business has six telephone lines. Lethenpte the number of lines in use at a specied time. Suppose the pmf oins as given in the accompanying table. X'U 1 2 3 4 5 6 p(x)'0.ll 0.15 0.20 0.25 0.19 0.0? 0.03 Calculate the probability of each of the following events. (a) {at most three lines are in use} :I (b) {fewer than three lines are in use} :l [c] {at least three lines are in use} :I (d) {between two and ve lines, inclusive. are in use} :I (e) {between two and four lines, inclusive, are not in use} :I (f) {at least fourlines are not in use} :I