A mobile home fabricator has an annual demand of 10,000 units for a small refrigerator. The supplier sells the units for $100 in order quantities below 125 and $95 in order quantities above 124 units. The order cost is $5, and the annual holding cost is 10% of the unit value. If an incremental quantity discount schedule is in effect.

What is the optimum lot size for the refrigerator?
What is the total cost for optimum lot size for the refrigerator?