Modeling & Simulation

I need an answer ASAP fast

7. Customers arrive at a one man barber shop according to a Poisson process with a mean interarrival time of 15 minutes. Customers spend an average of 12 minutes in the barber's chair. (Assume exponential service time). (i) (242 marks) What is the expected number of customers in the barber shop? (ii) (22 marks) What is the expected number of customers in the queue? (iii) (212 marks) How much can a customer expect to spend in the barber shop? (iv) (212 marks) What is average time customers spend in the queue