1. Problem: 30 is 20% of what number? We need to find the number $x$ such that $20\%$ of $x$ is 30. 2. Express mathematically: $$0.20 \times x = 30$$ 3. Solve for $x$: $$x = \frac{30}{0.20} = 150$$ --- 4. Problem: What percent of 80 is 20? Find percentage $p$ such that $p\%$ of 80 equals 20. 5. Express mathematically: $$\frac{p}{100} \times 80 = 20$$ 6. Solve for $p$: $$p = \frac{20 \times 100}{80} = 25$$ --- 7. Problem: A shirt originally costs 500 and has a 20% discount. Find the discount amount. 8. Calculate discount: $$\text{discount} = 20\% \times 500 = 0.20 \times 500 = 100$$ --- 9. Problem: A student scored 45 out of 60. What percent did the student score? 10. Calculate percentage: $$\text{percent} = \frac{45}{60} \times 100 = 75\%$$ --- 11. Problem: A bag costs 1200 with a 25% discount. Find the sale price. 12. Calculate discount: $$\text{discount} = 25\% \times 1200 = 0.25 \times 1200 = 300$$ 13. Sale price: $$1200 - 300 = 900$$ --- 14. Problem: A jacket originally priced 1500 offered at 10% discount. Find discount amount. 15. Calculate discount: $$10\% \times 1500 = 0.10 \times 1500 = 150$$ --- 16. Problem: A bicycle is priced 4000 with 15% discount. Find sale price. 17. Calculate discount: $$15\% \times 4000 = 0.15 \times 4000 = 600$$ 18. Calculate sale price: $$4000 - 600 = 3400$$ --- 19. Problem: What is the value of $3^2$? 20. Calculate: $$3^2 = 9$$ Final answers: 12: $150$ 13: $25\%$ 14: $100$ 15: $75\%$ 16: $900$ 17: $150$ 18: $3400$ 19: $9$