Case Defence sells smartphone cases and uses the perpetual inventory system. The following is information on the purchases and sales of Defender Box cases. On October 1, Case Defence had 28 units with a unit cost of $22.

Purchases Sales

Date Units Unit Cost Units Unit Price

Oct. 3 18 23

Oct. 6 23 $ 58

Oct. 12 28 25

Oct. 19 28 $ 58

Oct. 23 38 27

Oct. 30 33 $ 58

Oct. 31 23 28