pls dont use AI. only answer if you know the concept. show all the formulas and calculations.

6. The arrival of employees in a service station (canteen) follows Poisson distribution, and service times are exponentially distributed. The rate of arrivals averages 45 employees each hour, and an attendant can serve on an average 50 employees each hour. The employees are paid Rs. 8 per hour, and the attendants are paid Rs. 5 per hour. Find the optimum number of attendants to be placed in the service station.