In accounting, can you explain the calculation and significance of the following financial ratios: current ratio, quick ratio, debt-to-equity ratio, and gross profit margin? How do these ratios help in assessing a company's liquidity, solvency, profitability and efficiency? Can you provide an example of how these ratios can be used to compare the performance of two companies in the same industry and how do these ratios may be affected by the company's size and business model?"