The average of four numbers 70, x6, 5x and 11x is 71. If x represents the same digit, then x² + 1 is equal to

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?

Five years ago, the average age of X₁, X₂, X₃ and X₄ was 50 years. If we include X₅, the present average age of all five is 56 years. Then the present age of X₅ is

Average of 13 results is 65, if the average of first seven results is 62 and the average of last seven results is 67, then the seventh result is :

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