What is demand comprised of

Frolic corporation has budgeted sales and production over the next quarter as follows. the company has 4100 units of product on hand at july 1. 10% of the next months sales in units should be on hand at the end of each month. october sales are expected to be 72000 units. budgeted sales for september would be: july august september sales in units 41,500 53,500 ? production in units 45,700 53,800 58,150