1. **Problem:** In 2007, find the number of housewives affected by malaria. 2. **Given:** Total people surveyed = 1000. Percentage affected in 2007 = 30%. Percentage of housewives among affected = 10%. 3. **Formula:** Number of housewives affected = Total people × Percentage affected × Percentage of housewives 4. **Calculation:** - Calculate 30% of 1000: $1000 \times \frac{30}{100} = 300$ - Calculate 10% of 300: $300 \times \frac{10}{100} = 30$ 5. **Answer:** 30 housewives were affected by malaria in 2007. 6. **Explanation:** First find how many people were affected (30% of 1000), then find how many of those were housewives (10% of affected). 7. **Tip:** To calculate percentages without a calculator, convert percentages to fractions and multiply stepwise. 8. **Final answer:** 30 Repeat this stepwise approach for each question, breaking down percentages and ratios into fractions and multiplying stepwise to find the answer without a calculator.