There are 10 bangles in a gift box. The average weight of the first 4 bangles is 74 grams and the average weight of the remaining 6 bangles is 75 grams. Find the overall average weight of all the bangles.

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).