In an Effort to Persuade Customers to Reduce Their Electricity

Essay

In an effort to persuade customers to reduce their electricity consumption during business hours, special discounts have been offered to low-consumption customers. One hydroelectric company estimates that 70% of the local residences have qualified for these discounts.
a. If we randomly select four residences, what is the probability exactly two of the four will have qualified for the discounts?
b. If, instead, a sample of 20 residences is selected, what is the probability 12 or more will have qualified for the discounts?