Inventory Management : Please answer bolded question and show work!

You are working for a local Halloween store. The store decides to stock a popular costume that will only sell this year. It will not be useful after October 31st. The store can purchase the costume for $25 each. The store will be able to sell the costume for $65 each. Any leftover costumes can be sold to the local consignment store at $5 each. Assume that the demand follows a uniform distribution U(100,400). 21. How many units should the store order