Out of five numbers A, B, C, D and E, the average of the first four numbers A, B, C and D is greater than the average of the last four numbers B, C, D and E by 35. What is the value of (A - E)/7?

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).