a mailorder computer business has six telepone lines let x d

a mail-order computer business has six telepone lines. let x denote the number of lines in use at a specified time. suppose the mass function of x is given by

x

what proportion of the time will:

a.) at least five lines be in use?

b.)be between two and four lines, inclusive, be in use?

c.) at least four lines not be in use?

Solution

a. 0.10

b. 0.20 + 0.25 + 0.20 = 0.65

c. 1 - 0.30 = 0.70