Average of 21 number is 36. If the average of first 12 numbers is 15, then find the average of remaining 9 number?

In a primary school 96 students are studying. Their average weight is 30 kg. If a student shift to another school the average weight is increased by 200 gm. Find the weight of the student who shifted from the school.

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 average weight of A, B, and C is 52 kg. If the average weight of B and C is 44 kg and that of C and A is 46 kg, then what will be the weight of C?

The average of 5 numbers is 27. If one number is excluded, the average becomes 25. The excluded number is: 

In a year, the average expenditure of a family for the first 3 months, next 4 months and last 5 months is Rs 8400 per month, Rs 10080 per month, Rs 10608. Monthly and annual savings are Rs. 8640. If so, what is the average monthly income of this family?

The average of 100 numbers is 44. The average of these 100 numbers and 4 other new numbers is 50. The average of the four new numbers will be

The total average salary of 50 employees in a company is Rs 5,000. If there are 35 male employees among these employees whose average salary is Rs 6,000, then what will be the average salary of the remaining female employees?