The average age of 25 students in a class is 14 years. Five new students with an average age of 14.6 years join this class. What is the average age of 30 students in the class?

The average of 100 numbers is 40. If one of the numbers, 30, is replaced by 70 while keeping the other numbers same, what is the new average?

The arithmetic mean of 22.5, 56, 42.5, 2x + 1, x - 2, 3x, and 36 is 30. Find the value of x (where x > 0).