3.22 ([1] 3.70) An oil prospector will drill a succession of holes in a given area to find productive well. The probability that he is successful on a given trial is

0.2. a) What is the probability that the third hole drilled is the first to yield a productive well? b) If the prospector can afford to drill at most ten wells, what is the probability that he will fail to find a productive well? c) The prospector drills holes until he finds a productive well. How many holes would the prospector expect to drill?