On a table in front of you is a small freezer that is capable of holding seven standard ice cube trays stacked on top of each other. There are no shelves to separate the trays, and if you stack one tray on top of another before the ice cubes in the bottom tray are fully frozen, the top tray will sink into the bottom tray and you will not be able to make full-sized ice cubes. You have an unlimited supply of trays, each of which can make a dozen ice cubes.
If it takes fifteen minutes for the water to freeze completely into an ice cube, what is the maximum number of full-sized ice cubes you can produce in sixty minutes?
As per my calculation, one can do 120 cubes each time. Since it takes 15 minutes to make an ice cube, 120X4=480 would be the answer. However, need some validation on whether the maths is correct.
Seems like a few of us have presumed we are allowed to break or mutilate the trays, unfortunately, it is not part of the deal.