Can someone provide step-by-step solutions to the problem? I provided the correct answer from my textbook so that you can check your answer. Thanks in advance!

5. Minimizing inventory costs. A tee-shirt company sells 4000 sweatshirts per year. To reorder, there is a fixed cost of $6 plus $0.80 for each sweatshirt. It costs $1.20 to store one sweatshirt for one year. In what lot size and how many times per year should an order be placed to minimize inventory costs