A "handoff" of a cell phone system is the process in which a phone changes from one tower to another while the user moves during a call. Suppose a person is driving on the highway at a speed of 60 miles/hour, in which there are cell towers placed every 3 miles. Also, suppose that the duration of this person's calls can be modeled as an exponential random variable with a average duration of 10 minutes. Assume that handoffs occur midway between rooks, and that the person starts a call immediately after their phone switches to a new tower. a. What is the probability that the person's phone will experience at least 3 handoffs dunngthe call? b. What is the probability that the person's phone will experience at most 4 handoffs dunngthe call? c. Given that the phone has experienced 4 handoffs, what is the probability of experiencing at least 7 "handoff"