A machine tool is idle 15% of the time.

A machine tool is idle 15% of the time. You request immediate use of the tool on five different occasions during the year. Assume that your requests represent independent events.,(a) What is the probability that the tool is idle at the time of all of your requests?,(b) What is the probability that the machine is idle at the time of exactly four of your requests?,(c) What is the probability that the tool is idle at the time of at least three of your requests?