Q. Jake Tweet hosts a psychology talk show on KRAN radio. Jake's advice average 10 minutes per caller but varies according to an exponential distribution. The average time among calls is 25 minutes, exponentially distributed. Generating calls in this local market is difficult, so Jake does not want to lose any calls to busy signals. The radio station has only three telephone lines. Illustrate what is the probability which a caller receives a busy signals? Elucidate clearly by showing all your work.