1. **Problem Statement:** We have 400 kg of rice. The owner sells 80% of it at 20 per kg. We need to: a) Express 80% as a ratio and decimal. b) Find how many kg of rice he sells and the total selling price. c) If the selling price increases by 400, find the new amount of rice sold. 2. **Formulas and Rules:** - Percentage to decimal: divide by 100. - Percentage to ratio: write as fraction and simplify. - Total selling price = quantity sold $ \times $ price per kg. 3. **Step a:** - 80% as decimal: $$80\% = \frac{80}{100} = 0.8$$ - 80% as ratio: $$80\% = \frac{80}{100} = \frac{4}{5}$$ 4. **Step b:** - Quantity sold: $$400 \times 0.8 = 320\text{ kg}$$ - Total selling price: $$320 \times 20 = 6400$$ 5. **Step c:** - New selling price: $$6400 + 400 = 6800$$ - Let new quantity sold be $$x$$ kg. - Price per kg remains 20. - So, $$20x = 6800$$ - Solve for $$x$$: $$x = \frac{6800}{20} = 340\text{ kg}$$ **Final answers:** a) Ratio: $$\frac{4}{5}$$, Decimal: $$0.8$$ b) Sold rice: 320 kg, Total price: 6400 c) New sold rice amount: 340 kg