1. Write the given percentages as decimals. (a) 74% = $\frac{74}{100} = 0.74$ (b) 62% = $\frac{62}{100} = 0.62$ (c) 122% = $\frac{122}{100} = 1.22$ (d) 472% = $\frac{472}{100} = 4.72$ (e) 97% = $\frac{97}{100} = 0.97$ (f) 12.5% = $\frac{12.5}{100} = 0.125$ (g) 478% = $\frac{478}{100} = 4.78$ (h) 310% = $\frac{310}{100} = 3.10$ (i) 27.5% = $\frac{27.5}{100} = 0.275$ 2. Sanjay spent $\frac{25}{100}$ of his salary on food. The rest he saved. Percentage saved = $100\% - 25\% = 75\%$ 3. I ate $\frac{3}{10}$ of a pizza. Percentage eaten = $\frac{3}{10} \times 100\% = 30\%$ 4. 350 people watched a movie. 60% liked it. People who did not like = $40\%$ of 350 = $\frac{40}{100} \times 350 = 140$ 5. Bill amount = 640, service charge = 5% of 640 Service charge = $\frac{5}{100} \times 640 = 32$ Total amount = $640 + 32 = 672$ 6. 40 people in shop, 30% bought something. People who did not buy = $70\%$ of 40 = $\frac{70}{100} \times 40 = 28$ 7. $\frac{2}{3}$ students have dark hair. Percentage with dark hair = $\frac{2}{3} \times 100\% = 66.67\%$ Percentage without dark hair = $100\% - 66.67\% = 33.33\%$ 8. Price = 45000, discount = 20% Discount amount = $\frac{20}{100} \times 45000 = 9000$ Price to pay = $45000 - 9000 = 36000$ 9. Sudha bought at 55% of original price. Discount = $100\% - 55\% = 45\%$ 10. Track length = 15 km, jogged = 9 km Percentage jogged = $\frac{9}{15} \times 100\% = 60\%$ 11. Marian earned 45000. Spent on food = 20% of 45000 = $\frac{20}{100} \times 45000 = 9000$ Spent on rent = 45% of 45000 = $\frac{45}{100} \times 45000 = 20250$ Total spent = $9000 + 20250 = 29250$ Saved = $45000 - 29250 = 15750$ 12. Class of 40 students, 60% present. Number present = $\frac{60}{100} \times 40 = 24$ 13. Prize = 8000, income tax = 10% Tax paid = $\frac{10}{100} \times 8000 = 800$ Money after tax = $8000 - 800 = 7200$ 14. Necklace weight = 100 g, silver = 70% Weight of silver = $\frac{70}{100} \times 100 = 70$ g Weight of diamonds = $100 - 70 = 30$ g 15. Population = 4500000, children = 25% Number of children = $\frac{25}{100} \times 4500000 = 1125000$ Number of adults = $4500000 - 1125000 = 3375000$