The average salary of the entire staff in an office is Rs 3200 per month. The average salary of officers is Rs 6800 and that of non-officers is Rs 2000. If the number of officers is 5, then find the number of non-officers in the office.

In a class, there are 30 girls and 15 boys and total average weight of class is $$47{7\over15}$$ kg. The total average weight of boys is 58 kg. Find the approximate average weight of girls. 

The number of students in section A and section B of a class are 40 and 52, respectively. The average score in mathematics of all the students is 75. If the average score of the students in A is 20% more than that of students in B. then what is the average score of students is B?

The average of twenty-five numbers is 54. The average of the first 13 numbers and that of the last 13 numbers is 52.8 and 62.2, respectively. If the 13th number is excluded, then what is the average of the remaining numbers (correct to one decimal place)?

The average score in Mathematics of 90 students of section A and B of class IX was 63. The number of students in A were 10 more than those in B. The average score of students in A was 30% more than that of students in B. The average score of students in B is:

The average of three numbers a, b and c is 2 more than c. The average of a and b is 48. If d is 10 less than c, then the average of c and d is:

Find the average of the following sets of numbers.

693, 456, 876, 532, 934, 691, 596, 398, 682

The average weight of three men is increased by 4 kg when one of them, whose weight is 100 kg, is replaced by another man. What is the weight of the new man?