1.Revenue Canada spends, on the average, 30 minutes per income tax return it decides to audit. These audit times are known to be normally distributed with a standard deviation of 10 minutes.

a.Suppose a tax return is selected at random for audit. What is the probability that it will take less than 24 minutes to complete the audit?

b.In less than how many minutes that 90% of all these returns can each be audited?

c.Suppose two tax returns are selected at random. What is the probability that at least one of the two will take less than 24 minutes to audit?

d.Suppose 5 returns are selected at random. What is the probability that the average time taken to audit these 5 returns will be at least 24 minutes?