Chapter 7 - Functions - Exercise Set 7.2 - Page 414: 19

$ a-position\,6\\ b-position\,4\\ c-position\,1 $

$Hash(n)=n\,mod\,7=n-7(n\,div\,7)\\ a-\\ social\,number\,: 417-30-2072 \\ Hash(417302072)=417302072\,mod\,7=417302072-7(59,614,581)=5\\ but\,position\,5\,is\,occupied\,but\,position\,6\,is\,not\,\\ so\,add\,the\,social-number\,in\,position\,6 \\ b-\\ social\,number\,: 364-98-1703\\ Hash(364,981,703)=364,981,703\,mod\,7=364,981,703-7(52,140,243)=2\\ but\,position\,2\,is\,occupied\,(and\,3)\,but\,position\,4\,is\,not\,\\ so\,add\,the\,social-number\,in\,position\,4 \\ c-\\ social\,number\,: 283-09-0787\\ Hash(283,090,787)=283,090,787\,mod\,7=283,090,787-7(40,441,541)=0\\ but\,position\,0\,is\,occupied\,but\,position\,1\,is\,not\,\\ so\,add\,the\,social-number\,in\,position\,1 \\ $