document.write( "Question 30425: What is the number of different 7 digit numbers that can be made by rearranging the digits 3053354? \n" ); document.write( "
Algebra.Com's Answer #17087 by longjonsilver(2297)![]() ![]() You can put this solution on YOUR website! if all the numbers were different, we would have 7! permutations... which is 5040 different numbers.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Additional thing to think about would be numbers like 0123456.. this is not a recognised number, so we cannot have the zero in the \"first position\".\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So... \n" ); document.write( "First position: how many numbers could we have? Answer is 6 (as the zero is not allowed there).\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Second position: how many numbers? Well any of the 6 remaining. \n" ); document.write( "Third position: Any of the 5 remaining \n" ); document.write( "fourth position: Any of the 4 remaining \n" ); document.write( "and so on.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Total: 6*6*5*4*3*2*1 --> 6*6! --> 6*720 --> 4320.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Notice, this is 720 less than 5040 ie it is one whole block of 6!\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now, this is not the final answer, since there are three 3's and two 5's, so there is going to be repetition of certain numbers.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Total number of different numbers = 4320/(3!2!) \n" ); document.write( "Total number of different numbers = 4320/(6*2) \n" ); document.write( "Total number of different numbers = 4320/12 \n" ); document.write( "Total number of different numbers = 360\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So, there are just 360 different numbers that can be made up from the given set of digits.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "jon. \n" ); document.write( " \n" ); document.write( " |