mathschallenge.net logo

Kitchen Floor

Problem

A kitchen floor is to be tiled in the following way,


If the kitchen measures 15 tiles x 25 tiles, how many white tiles will be needed?


Solution

The floor is made up of a 2x2 repeating pattern,


A 15 times 25 floor will fit 7x12 repeating blocks (14x24 tiles). The "end" lines will be all white.

So there will be 7 times 12 = 84 grey tiles.

Hence there will be 15 times 25 minus 84 = 374 minus 84 = 291 white tiles.

What about a kitchen measuring m times n tiles?

Problem ID: 92 (Dec 2002)     Difficulty: 1 Star

Only Show Problem