Some heavy boxes are to be loaded along with some empty boxes on a cart. Which boxes should be put on the cart first and why ?

Some solid cubes are to be loaded along with some hollow cubes of same material on cart. Which cubes should be put on the cart first and why?

There are five different boxes and seven different balls.All the seven balls are to be distributed in these boxes.The number of ways can they be distributed so that no box remains empty are

5 balls are to be placed into 3 boxes such that no box remains empty The number of ways in which this can be done.

The number of ways of distributing 7 different balls into 5 different boxes.So that no box is empty and order of putting the balls in the boxes is considered is 15n. The value of n is

Oranges are to be transferred from larger boxes into smaller boxes.When a large box is emptied,the oranges from it fill two smaller boxes and still 10 oranges remain outside.If the number of oranges in a small box are taken to be x,what is the number of oranges in the larger box?