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

Three years ago, the average age of Anita, Priya, and Varsha was 27 years. If five years ago, the average age of Priya and Varsha was 20 years, find the present age of Anita.

Four years ago, the average age of A and B was 20 years. If today average age of A, B and C is 25 years, what will be age of C after 7 years?

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.

The average age of 30 boys in a class is 15 years. If we include the age of two teachers the average age increases by 1. Find the sum of ages of the two teachers.

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?