document.write( "Question 87547: How may different 5-digit numbers that are odd and less than 50,000 can be formed using the digits 2,3,4,5,6,7 and 8 without repetition? \n" ); document.write( "
Algebra.Com's Answer #258795 by sudhanshu_kmr(1152)![]() ![]() You can put this solution on YOUR website! At unit place only one of these are possible 3,5,or 7.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Case A (when 3 at unit place i.e fifth position) : \r \n" ); document.write( "\n" ); document.write( "for first position i.e _xxxx only 2 or 4 is possible otherwise it will greater \r \n" ); document.write( "\n" ); document.write( "than 50,000\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "so, no. of ways to fill first position = 2 (two digits have used )\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "now, no. of ways to fill second position = 5 ( only 5 digits are remaining)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "no. of ways to fill third position i.e xx_xx = 4 (only 4 digits are remaining)\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "no. of ways to fill fourth position = 3 (only 3 digits are remaining)\r \n" ); document.write( "\n" ); document.write( "fifth position is already occupied by 3.\r \n" ); document.write( "\n" ); document.write( "so, total no. of different numbers that can be formed = 2 * 5 * 4 * 3 =120 \n" ); document.write( "..........................................................................\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Case B (when 5 at unit place i.e fifth position) : \r \n" ); document.write( "\n" ); document.write( "for first position i.e _xxxx only 2, 3 or 4 is possible otherwise it will \r \n" ); document.write( "\n" ); document.write( "greater than 50,000\r \n" ); document.write( "\n" ); document.write( "so, no. of ways to fill first position = 3 (two digits have used )\r \n" ); document.write( "\n" ); document.write( "now, no. of ways to fill second position = 5 ( only 5 digits are remaining)\r \n" ); document.write( "\n" ); document.write( "no. of ways to fill third position i.e xx_xx = 4 (only 4 digits are remaining)\r \n" ); document.write( "\n" ); document.write( "no. of ways to fill fourth position = 3 (only 3 digits are remaining)\r \n" ); document.write( "\n" ); document.write( "fifth position is already occupied by 5.\r \n" ); document.write( "\n" ); document.write( "so, total no. of different numbers that can be formed = 3 * 5 * 4 * 3 =180\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "............................................................................... \n" ); document.write( "Case C (when 7 at unit place i.e fifth position) : \r \n" ); document.write( "\n" ); document.write( "similarly,\r \n" ); document.write( "\n" ); document.write( "so, no. of ways to fill first position = 3 (two digits have used )\r \n" ); document.write( "\n" ); document.write( "now, no. of ways to fill second position = 5 ( only 5 digits are remaining)\r \n" ); document.write( "\n" ); document.write( "no. of ways to fill third position i.e xx_xx = 4 (only 4 digits are remaining)\r \n" ); document.write( "\n" ); document.write( "no. of ways to fill fourth position = 3 (only 3 digits are remaining)\r \n" ); document.write( "\n" ); document.write( "fifth position is already occupied by 7.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "so, total no. of different numbers that can be formed = 3 * 5 * 4 * 3 =180\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "now we add the value of these three cases.\r \n" ); document.write( "\n" ); document.write( "no. of different 5-digit numbers that are odd and less than 50,000 can be \r \n" ); document.write( "\n" ); document.write( "formed = 120 + 180 + 180 = 480\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "It is possible that some typing mistake in solution of a problem, if any please ignore it. Understand the concept and try to solve the problem yourself. If there is problem related to concept, contact at \n" ); document.write( "sudhanshu.cochin@yahoo.com or sudhanshu.cochin@gmail.com \n" ); document.write( "Best of luck....... \r \n" ); document.write( "\n" ); document.write( "waiting for your reply......\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |