Please help. Thank you

Mary Goswing is a trader. She does not operate a full double entry system but she does keep books of prime entry from which control accounts are prepared. The following information relates to the year ended 30 April 2005: Debtors control account balance 1 May 2004 Debtors control account balance 30 April 2005 Receipts from debtors Receipts from cash sales Bad debt written off Discount allowed $ $ $ $ $ $ 24.000 48.000 120.000 18.000 4.000 6.000 1/Calculate the total sales for the year ended 30 April 2005 2/Explain two ways in which control accounts can be used by Mary Goswing in her business. 3/Suggest two limitations to the usefulness of control accounts in Mary Goswing's approach to record keeping