The average runs scored by a batsman in 21 innings is 37. He scored 'x' runs in the 22nd inning such that his overall average increased by 2 runs. Find the value of 'x'.

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).