Item X is a standard item stocked in a company’s inventory of component parts

Item X is a standard item stocked in a company’s inventory of component parts. Each year the
firm, on a random basis, uses about 2,000 of item X, which costs $25 each. Storage costs, which
include insurance and cost of capital, amount to $5 per unit of average inventory. Every time an
order is placed for more item X, it costs $10.
a. Whenever item X is ordered, what should the order size be?
b. What is the annual cost for ordering item X?
c. What is the annual cost for storing item X?