Q Co. prepares monthly income statements. A physical inventory is taken only at year end; hence, month-end inventories must be estimated. All sales are made on account. The rate of markup on cost is 50%. The following information relates to the month of June: Accounts receivable, June 1 $10,000 Accounts receivable, June 30 15,000 Collection of accounts receivable during June 25,000 Inventory, June 1 18,000 Purchases of inventory during June 16,000 The estimated cost of the June 30 inventory is .