During the first hour a store is open, twenty customers enter the store. The store has regular checkout
lanes for any number of items and a quick-check lane for customers with 10 items or less. From store
records, the probability that a randomly chosen customer purchases more than ten items is 0.75.
Assume that each customer shops independently of each other.

a. What is the probability the all twenty customers purchase more than 10 items so the quick-check
lane will not be needed?

b. What is the probability at least one customer purchases 10 items or less, so the quick-check lane
will be needed?