Understanding the relationship between RGB and Hexadecimal

<body> <center>Sorry you do not have frames enabled. Here is the link of the tutorial:<br> <a href="http://www.pixel2life.com/publish/tutorials/164/using_php_to_convert_between_hex_and_rgb_values/">http://www.pixel2life.com/publish/tutorials/164/using_php_to_convert_between_hex_and_rgb_values/</a></center> </body>