7169 /www/nrich/html/content/id/7169/ 1 2011-02-01T00:00:01 <?xml version="1.0" encoding="UTF-8"?> <mdoxml version="1.0"><br></br> <p>A tile is fixed to a wall and then painted with four different colours, one for each quarter. One way of doing this is <br></br>  <mdo:image alt="" height="177" src="2011%2021.PNG" width="351"></mdo:image><br></br> How many other ways can the tile be painted?<br></br>  <br></br>  <br></br> If you liked this problem, <a href="http://nrich.maths.org/6237&amp;part=">here is an NRICH problem</a> <a href="http://nrich.maths.org/529"></a>which is based on similar mathematical ideas  <br></br>  </p></mdoxml> <?xml version="1.0" encoding="UTF-8"?> <mdoxml version="1.0"><br></br> In total there are $24$ different ways to paint the tile, which means there are $23$ <span style="font-weight: bold;">other</span> ways to paint it.<br></br>  <br></br>  <br></br></mdoxml> 2 3 0 1 1 0 0 Weekly Problem 21 - 2011 Numbers and the Number System Counting Decision Mathematics and Combinatorics Combinations Decision Mathematics and Combinatorics Permutations