Professor Layton and the Curious Village/Puzzles 76-100

Puzzle 076

 * Name:A Tile Square
 * Trigger:Talk to mad guy by park
 * Location:by park
 * Chapter:
 * Picarats:24

Description:You have at your disposal a large number of tiles like the one shown below. If you were to take these tiles and try to make a square,What is the fewest number of tiles you'd need?

Of course the puzzle doesn't end there.You'll need to do a little creative thinking in order to find the fewest number of tiles that allow you to form a square. Too simple,in fact,There's a way to make a square using even fewer tiles.
 * Hint 1:Since the tiles have a different lenght and width,you'll need to find a number that can be divided by both dimensions.
 * Hint 2:Don't forget the puzzle also gives you the THICKNESS of the tiles.
 * Hint 3:As the sides of the tiles are 10 and 12 inches long,the smallest common multiple of the two works out to 60.Therefore,you'll need to arrange a 5x6 tile square.Thats a total of 30 tiles.Simple right?

Answer:20 The key to this problem is realizing that the tiles have depth to them.Once you understand that you have a third dimension to work with,the rest should fall into place for you.