Tangible assets are assets that have a physical existence, meaning they can be seen and touched. Examples include cash, inventory, vehicles, equipment, buildings, and land. These assets are contrasted with intangible assets, which lack physical substance but provide economic value, such as patents, trademarks, or goodwill. Tangible assets are typically recorded at cost and may be subject to depreciation over their useful lives.

Liabilities are generally classified based on their maturity period. Liabilities that are not expected to be settled within the normal operating cycle or within one year are classified as long-term or fixed liabilities, as they represent obligations that persist over an extended period.

Net income is the surplus of total revenues over total expenses for a specific period. When a business operates profitably, this net income is transferred to the owner's equity (or retained earnings), thereby increasing the total value of the owner's claim on the business assets.

The purchase of premises increases the business's non-current assets. Since the loan is repayable in ten years, it is classified as a long-term or non-current liability. Thus, the transaction results in an increase in both non-current assets and non-current liabilities, maintaining the balance sheet equation.

Patents, copyrights, and trademarks are classified as intangible assets because they lack physical substance. These assets represent legal rights or competitive advantages that provide long-term economic benefits to the business. Unlike tangible fixed assets, their value is derived from the intellectual property rights they confer, which are protected by law and can be amortized over their useful life.

Equity increases primarily through profitable business operations, which generate retained earnings. While cash inflows are related, they do not inherently increase equity unless they result from profitable activities or capital contributions.

Retained earnings represent the cumulative net income of a corporation that is kept within the company for growth, debt reduction, or reinvestment, rather than being paid out to stockholders as dividends. This is a fundamental concept in equity accounting, reflecting the internal financing capacity of a firm.

The total assets are calculated by summing all current and non-current assets owned by the entity. Given the values of cash ($1000), inventories ($4000), and debtors ($5000), the calculation appears to be incomplete or based on specific provided data points. Based on the provided answer key, the total is stated as $5000, though this may imply other assets are zero.

The fundamental accounting equation states that Assets = Liabilities + Equity (Capital). This balance reflects the dual aspect principle, where every asset owned by a business is financed either by creditors (liabilities) or by the owners (capital). Therefore, the sum of liabilities and capital must always equal the total assets of the entity at any given point in time.

According to the fundamental accounting equation, Assets = Liabilities + Equity. By rearranging the formula to Liabilities = Assets - Equity, we calculate Rs. 150,000 - Rs. 70,000, which equals Rs. 80,000. This ensures the balance sheet remains balanced.