The average of 6 numbers is 5. The first number is increased by 2, second by 4, third by 8 and so on. The average of new numbers is

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

The average age of 4 sisters is 7 years. If we add the age of mother, then the average increases by 6 years. Find the age of the mother.

Find the average of first 20 consecutive 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

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?