prepare general journal entries

GST is 10%. March 3 Purchased 100 units for $70 each plus GST, on credit. 8 Returned 8 units which were unsuitable. 11 Sold 60 units for $90 each plus GST, on credit. 16 Customer returned 8 units sold on 11 March. 18 Received amount due from customer who made the March 11 purchase. 22 Optimus sold 15 units for a total of $1500 plus GST, terms 2/10, N30 25 The customer paid the amount due. 30 The physical inventory stocktake at the end of the month consisted of 5 fewer units than the inventory account balance