In a city, 12% of households earn less than Rs. 30,000 per year, 6% households earn more than Rs. 2,00,000 per year, 22% households earn more than Rs. 1,00,000 per year and 990 households earn between Rs. 30,000 and Rs. 1,00,000 per year. How many households earn between Rs. 1,00,000 and Rs. 2,00,000 per year?

Here's a brief explanation:

1. Identify known percentages:

   • Households earning less than Rs. 30,000 = 12%
   • Households earning more than Rs. 1,00,000 = 22%

2. Calculate the percentage of households earning between Rs. 30,000 and Rs. 1,00,000:

   • This group covers the remaining percentage after accounting for those below Rs. 30,000 and those above Rs. 1,00,000.
   • Percentage = 100% - (Percentage Rs. 1,00,000)
   • Percentage = 100% - 12% - 22% = 66%

3. Determine the total number of households:

   • We are given that 990 households earn between Rs. 30,000 and Rs. 1,00,000.
   • Since this represents 66% of the total households, let T be the total households.
   • 0.66 * T = 990
   • T = 990 / 0.66 = 1500 households

4. Calculate the percentage of households earning between Rs. 1,00,000 and Rs. 2,00,000:

   • Households earning more than Rs. 1,00,000 = 22%
   • Households earning more than Rs. 2,00,000 = 6%
   • Percentage (Rs. 1,00,000 - Rs. 2,00,000) = (Percentage > Rs. 1,00,000) - (Percentage > Rs. 2,00,000)
   • Percentage = 22% - 6% = 16%

5. Calculate the number of households in the target range:

   • Number of households = 16% of Total Households
   • Number = 0.16 * 1500 = 240

Therefore, 240 households earn between Rs. 1,00,000 and Rs. 2,00,000 per year.

The final answer is B) 240.