1. If 30% of the people in a community use the library in one year, find these probabilities for a sample of 15 people:

(a)At most 7 used the library.

(b)Exactly 7 used the library.

(c)At least 5 used the library.

A sales firm receives, on the average, four calls per hour on its toll-free number. For any given hour, find the probability that it will receive the following:

(a)At most three calls

(b)At least three calls