Please answer the questions 15.5, 15.6 and 15.7 with your detailed explanations, it's much appreciated!

15.5 Which of the following items could appear on the credit side of a receivables ledger control account? (1) Cash received from customers (2) Irrecoverable debts written off (3) Increase in allowance for receivables (4) Sales (5) Credits for goods returned by customers (6) Cash refunds to customers 1,2 , and 5 1, 2, 3 and 6 3,4 and 5 4 and 6 An inexperienced bookkeeper has drawn up the following receivables ledger control account: What should the closing balance be after correcting the errors made in preparing the account? $130,600 $129,200 $142,400 $214,600 The payables ledger control account below contains a number of errors: PAYABLES LEDGER CONTROL ACCOUNT All items relate to credit purchases. What should the closing balance be when all the errors are corrected? $128,200 $509,000 $224,200 $144,600