Advanced accounting

Dear friends,

Please refer page No. 1.4 in the attachment. There is a problem given in the study material as an example. I could not understand:

1. How the depreciation amount became 13,000 in case 1 (in P & L account for 31/03/2011)

2. How the Fixed asset has become 52,000 in Balance sheet in case 1 (if the above doubt is clarified it will be automatically clarified)

3. How the trade payables is 12,000 in case 1 (is it assumed that if the company is not going concern the discount of 5% is not available)

Kindly clarify. I am not good at accounts. Request you to explain in detail.

Thanks in advance

Vinay