2. The daily dinner bills in a local restaurant are normally distributed with a mean of $28 and a standard deviation of $6.

a. What is the probability that a randomly selected bill will be at least $39.10?

b. What percentage of the bills will be less than $16.90?

c. What are the minimum and maximum of the middle 95% of the bills?

d. If twelve of one day's bills had a value of at least $43.06, how many bills did the restaurant collect on that day?