Times Books Warehouse is owned by Stephen Guy. It sells hardback books to retail stores and extends credit terms of 3/15, n/30 to all its customers. The business uses a perpetual inventory system to account for its inventory. The business has been registered for GST. GST rate is 10%. The following selected information is available for Times Books Warehouse." for the week ended 7 April 2021: 1st April Purchased 300 books on account for $20 (plus GST) each from 'Happy Publishes'. Credit Terms: 3/10, n/30. 2nd April Stephen Guy returned 10 books to Happy Publishes' (supplier) due to minor defects in printing of some the books. Sold 100 books on account to 'Readers-R-Us' for $30 (plus GST) each. 4th April 7th April Paid Happy Publishes (supplier) for 1st April purchases. REQUIRED: Prepare the journal entries to record each transaction in April 2021. (Narrations not required)