If x is the average of 1², 2², 3², ..., 10² and y is the average of first 10 even natural numbers, then y is what percent of x − y?

If M is the mean of the first 100 even natural numbers, then what is the mean of the first 100 odd natural numbers?

If the average of m numbers is n*n and that of n numbers is m*m , then the average of m+n numbers is

Find the average of first 20 consecutive natural numbers.

The average of square of first 6 consecutive even numbers is:

Let five odd consecutive natural numbers be P, Q, R, S and T. What is their average?