A manager must decide how many machines of a certain type to purchase. Each machine can process 100 customers per day. One machine will result in a fixed cost of $ 2,000 per day, while two machines will result in a fixed cost of $ 3,800 per day. Variable costs will be $ 20 per customer, and revenue will be $ 45 per customer.

a. Determine the break-even point for each range.

b. If estimated demand is 90 to 120 customers per day, how many machines should be purchased?