Z-Mart uses the perpetual inventory system and has its own credit card. Z-Mart charges a per-month interest fee for any unpaid balance on its store credit card at each month-end. Apr. 30 Z-Mart sold merchandise for $2,900 (that had cost $1,600) and accepted the customer’s Z-Mart store credit card. May 31 Z-Mart recorded $4 of interest earned from its store credit card as of this month-end. Prepare journal entries to record the above credit card transactions of Z-Mart.