Question:

The following information was extracted from the books of William Noel for the year ended 30 April 2009.
                                                                            Rs
Purchases Ledger Balance as at 1 May 2008    43120
Credit purchase for the year                             824 140
Credit purchases returns                                  12 400
Cheques paid to creditors                                 745 980
Cash purchases                                                 8 940
Discount received on credit purchases               31 400
Credit balances transferred to sales ledger accounts 5 210

The total of the balances in Noel's purchases ledger amounts to Rs 67 660, which does not agree with the closing balance in the Control account.

The following errors were then discovered:

1. Discount received had been overstated by Rs 1 000.
2. A credit purchases invoice for Rs 2 040 had been completely omitted from the books.
3. The purchases ledger account had been understated by Rs 100.
4. A credit balance of Rs 850 in the purchases ledger had been set off against a contra entry in the sales ledger, but no entry had been made in the control accounts.
5. A payment of Rs 1 450 had been debited to the creditor's account but was omitted from the bank account.
6. A credit balance of Rs 3 210 had been omitted from the list of creditors.

Required:

a. Prepare a Purchases Ledger Control Account for the year ended 30 April 2009.

b. Explain why it is useful to maintain a control account in respect of both trade receivables and trade payables.

c. Explain briefly how a contra entry might arise.