Show all calculations thank you. Mark Achin sells 3,600 electric motors each year.

Please need help show clear work please.... Show all calculations thank you....

Mark Achin sells 3,600 electric motors each year. The cost of these is $200 each, and demand is constant throughout the year. The cost of placing an order is $40, while the holding cost is $20 per unit per year. There are 360 working days per year and the lead-time is 5 days. If Mark orders 400 units each time he places an order, what would his average inventory be (in units)?