Veena’s financial year ends on 30 November. All sales are made on credit terms and the selling price is calculated by marking-up the cost price by 20%.

He does not maintain a full set of double entry records but was able to provide the following information:
                                                                                                                                     $
On 1 December 20–0:

Trade receivables ........................................................................................       3,620

During the year ended 30 November 20–1:

Amounts received from trade receivables ...............................................     36,750
Discount allowed to trade receivables ........................................................        750
Irrecoverable debts .......................................................................................        860

On 30 November 20–1:

Trade receivables .............................................................................................    4,020

a. Calculate the credit sales for the year ended 30 November 20–1.
b. Calculate the gross profit for the year ended 30 November 20–1.
c. Calculate the cost of sales for the year ended 30 November 20–1.
d. Suggest to Veena three advantages of maintaining a full set of double entry records.