The emergency room at HSI serves patients who arrive according to a Poisson distribution at the rate

Question:

The emergency room at HSI serves patients who arrive according to a Poisson distribution at the rate of 9 per hour. Treatment takes an average of 6 minutes and the treatment times can be considered to follow an exponential distribution. What is the

(a) Minimum number of doctors required so that at least 70% of the arriving patients can receive treatment immediately?

(b) Minimum number of doctors required so that the average time a patient waits for treatment is no more than 30 minutes as advertised? No more than 15 minutes?

Distribution
The word "distribution" has several meanings in the financial world, most of them pertaining to the payment of assets from a fund, account, or individual security to an investor or beneficiary. Retirement account distributions are among the most...