document.write( "Question 257183: Please help me solve this word problem: The sum of the digits of a two-digit number is 12. The number is 12 times the tens digit. Find the number. I need to know how you got the equations please. \n" ); document.write( "
Algebra.Com's Answer #189118 by Theo(13342)![]() ![]() You can put this solution on YOUR website! let a = the tens digit. \n" ); document.write( "let b = the ones digit.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "a + b = 12 (sum of the digits is equal to 12).\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "10a + b = 12*a (the number is 12 times the tens digit).\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "solve for a in the first equation to get a = 12-b.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "substitute for a in the second equation to get 10*(12-b) + b = 12*(12-b).\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "simplify to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "120 - 10b + b = 144 - 12b.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "combine like terms to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "120 - 9b = 144 - 12b.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "add 12b to both sides of the equation and subtract 120 from both sides of the equation to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "3b = 24\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "divide both sides of the equation by 3 to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "b = 8\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "if b = 8, then a = 4 because a + b = 8 + 4 = 12.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the number is 10*a + b = 40 + 8 = 48\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "48 is equal to 12*a = 12*4 = 48 so that part of the equation is good.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "a + b = 4 + 8 = 12 so that part of the equation is also good.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "your answer is the number is 48.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |