Novak Corp. began operations on July 1. It uses a perpetual inventory system. During July, the company had the following purchases and sales. Purchase nI July 1 July 6 July 11 July 14 July 21 July 27 $81 $86 $92 7 4 4 4 Calculate average cost for each unit. (For calculation and answers purpose round unit costs to 2 decimal places, e.g. 15.25.) July 1 $ July 6 $ July 11 July 14 July 21 July 27 $