Please include steps and explanations!!!

Ivanhoe Company began operations on July 1. It uses a perpetual inventory system. During July, the company had the following purchases and sales. Purchases Date Units Unit Cost Sales Units July 1 13 $ 56 July 6 10 July 11 9 $60 July 14 9 July 21 12 $64 July 27 11 (a1) Your answer is partially correct. Calculate average cost for each unit. (For calculation and answers purpose round unit costs to 2 decimal places, e.g. 15.25.)