Bill, the owner of the specialty store Calculators Only is planning a promotional offer in hopes of attracting more people into the store. He has 10 coffee mugs with the store's logo on it and plans to give one to each customer who spends more than $50. On the day of the promotion, 12 people buy something. Past sales data shows that 65% of customers who purchase something spend more than $50.

(a) What is the probability Bill will have exactly 3 coffee mugs left at the end of the day?

(b) What is the probability that Bill will have enough mugs so that every customer who spends more than $50 will receive a mug?