In an M/M/1 system, workers arrive at a tool crib at a rate of 20 per hour. The total time that workers spend when picking up the required tool is considered wasted. Workers are paid $6 per hour. The clerk at the tool crib can serve up to seven workers per hour and is paid $10 per hour. (a) What is the cost-minimal number of clerks? Show all work. (b) What is the expected time a worker will have to wait for the tool in any of the scenarios you have considered under (a)? (c) What would you expect to happen if the hourly wage of a clerk increases to $13 per hour? Explain in one sentence. Calculations are not required.