6. Schneider’s Plumbing and Heating, located in Fargo, North Dakota, has 300 accounts receivable distributed as follows:

Current 1–30 days past due 31–60 days past due 61–90 days past due Sent for collection 140 80 40 25 15 An auditor is coming to inspect Schneider’s financial records. Included in the auditor’s analysis is a randomly chosen sample of four accounts from the company’s collection of accounts receivable.

a. What is the probability that all of the accounts chosen by the auditor will be current accounts?

b. What is the probability that all of the accounts chosen by the auditor will be less than or equal to 60 days past due?

c. What is the probability that all of the accounts chosen by the auditor will be more than 60 days past due?

d. What is the probability that two of the accounts will be current, and two will be 1–30 days past due?