Average - General Questions

What is the average of the first 53 natural numbers?

The average of 5 numbers is 55. When one more number is added, the average becomes 56. What is the new number?

The average marks of a class of 43 students is 51 and that of another class of 27 students is 56. What is the average of all the students together?

The average of 16 numbers is 60. When one more number is added, the average becomes 64. What is the new number?

The average of 18 numbers is 23. When one more number is added, the average becomes 28. What is the new number?