Refer to the previous exercise and now suppose that the chance experiment terminates only when two nondefective batteries have been obtained.
a. Let A denote the event that at most three batteries must be examined before the chance experiment terminates. What outcomes are contained in A?
b. Let B be the event that exactly four batteries must be examined before the chance experiment terminates. What outcomes are in B?
c. What can be said about the number of possible outcomes for this chance experiment?