4 MacBurger’s is attempting to determine how many servers (or lines) should be available during the breakfast shift. During each hour, an average of 100 customers arrive at the restaurant. Each line or server can handle an average of 50 customers per hour. A server costs $5 per hour, and the cost of a customer waiting in line for 1 hour is $20.

Assuming that an M/M/s/GD/∞/∞ model is applicable, determine the number of lines that minimizes the sum of delay and service costs.