How many 3x5 rectangles are necessary to fully cover a 26x26 square?
Clearly, overlapping each other and/or the edges of the square is allowed.

The answer is 46, i.e. the minimum possible. Make 4 blocks of 8 tiles 20x6 placed at right angles to each other, starting from each corner. There will be a central area 14x14. Make a block of 3 tiles 5x9 placed at right angles to each other, starting from each corner. There will be a central area 4x4, which can be covered with just two tiles. 4*8=32, 4*3=12, plus 2=46.

There may well be other ways of doing it.

Edited on June 24, 2011, 1:16 am

Posted by broll on 2011-06-23 12:35:42