List of top Quantitative Ability and Data Interpretation Questions on Average

In an office with 8 employees, the average rating of all employees is 30. The average rating of the top five employees is 38, and the average rating of the bottom three employees is 25. Which of the following is not possible?

Average monthly expenditure for January--June is ₹ 3200. He spends ₹ 3000 (July), ₹ 3600 (Aug), ₹ 3900 (Sept), ₹ 4200 (Oct). If November’s expenditure is $50%$ of December’s and the average for the entire year is ₹ 3200, find November’s expenditure.