A salesman normally makes a sale(closes) on 80% of his presentations. Assuming the presentations areindependent, find the probability of each of the following.

a) He fails to close for the first time on his fourth attempt.

b) He closes his first presentation on his third attempt.

c) The first presentation he closes will be on his second attempt.

d) The first presentation he closes will be on one of his first three attempts.

a) The probability he fails to close for the first time on his fourth attempt is

nothing

.

(Round to four decimal places asneeded.)

b) The probability he closes his first presentation on his third attempt is

nothing

.

(Round to four decimal places asneeded.)

c) The probability the first presentation he closes will be on his second attempt is

nothing

.

(Round to four decimal places asneeded.)

d) The probability the first presentation he closes will be on one of his first three attempts is

nothing

.

(Round to four decimal places asneeded.)