An indoor air conditioning unit has a lifetime that is exponentially distributed with the mean of 730 days. When such air conditioning unit stops functioning, it is replaced immediately. a. What is the probability that more than 1095 days will pass before the air conditioning unit needs to be replaced? b. After how many days will 60% of such air conditioning units be replaced? c. An air conditioning unit has functioned for 1460 days. What is the probability that it will continue functioning for at least additional 365 days? d. How many air conditioning units are expected to function for less than 1825 days? e. Calculate the probability that exactly four air conditioning units would need to be replaced within a 1825-days time interval.