A batsman has a certain average of runs in 12 innings. He scores 96 runs in the 13th inning, thereby increasing his average by 5 runs. What is his average after the 13th inning?

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).