The emergency room serves patients who turn up according to the Poisson distribution at rate of 9 per hour.
Treatment takes the average of six minutes and treatment times can be considered to follow the exponential distribution.
What is (A) Minimum number of doctors compulsory so that at least 70% of arriving patients can receive treatment immediately? (B)Minimum number of doctors needed so that the average time the patient waits for treatment is no more than 30 minutes as advertised? No more than fifteen minutes?