In the ABC retail store customers arrive at an average 50 per shift. The store manager wants to calculate whether he should hire 1, 2, 3 or 4 salespeople.He has deter- mined that average waiting times will be 6 minutes with one salesperson, 3 minutes with two salespeople, 2 minutes with three salespeople, and 1 minute with four salespeople.He has estimated the cost per minute that customer wait at $1. The cost per salesperson per shift (including fringe benefits) is $70. How many sales people should be hired?