A mail-order computer software business has six telephone lines. Let x denote the number of lines in use at a specified time. The probability distribution of x is as follows:

X 0 1 2 3 4 5 6

P(x) 0.13 0.17 0.20 0.25 0.15 0.08 0.02

Calculate the probability of:

d. Between two and five lines (inclusive) are in use.

e. Between two and four lines (inclusive) are not in use.

f. At least one line is not in use.