Patterson Electronics supplies microcomputer circuitry to a company that incorporates microprocessors into refrigerators and other home appliances. One of the components has an annual demand of 250 units, and this is constant throughout the year. The carrying cost is estimated to be $1 per unit per year, and the ordering cost is $20 per order.

1.                 

   To minimize cost, how many units should be ordered each time an order is placed?

                 
2.                 

   How many orders per year are needed with the optimal policy?

                 
3.                 

   What is the average inventory if costs are minimized?

                 
4.                 

   Suppose the ordering cost is not $20 and Patterson has been ordering 150 units each tim