Purchases Sales April 1 (balance on hand) 540 @ $6.00 April 3 450 @ $10.00 4 1,350 a 6.08 9 1,260 @ 10.00 8 720 a 6.40 11 540 @ 11.00 13 1,080 a 6.50 23 1,080 @ 11.00 21 630 @ 6.60 27 810 @ 12.00 29 450 @ 6.79 4,140 4,770 (a1) Assuming that periodic inventory records are kept in units only, calculate the average-cost per unit. (Round answer to 2 decimal places, e.g. 2.76.)