document.write( "Question 1035728: The sum of the digits of a two-digit number is 11. When the numbers are reversed, the new number is 20 less than twice the original. What is the original number? \n" ); document.write( "
Algebra.Com's Answer #650383 by Theo(13342)![]() ![]() You can put this solution on YOUR website! let the 2 digits of the number be a and b.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "a is the tens digit. \n" ); document.write( "b is the units digit. \n" ); document.write( "the value of the 2 digit number is 10a + b.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the sum of the digits of the 2 digit number is 11. \n" ); document.write( "this means that a + b = 11.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "when the numbers are reversed, the new number is 20 less than twice the original number.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "this means that 10b + a = 2 * (10a + b) - 20.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "simplify this to get 10b + a = 20a + 2b - 20. \n" ); document.write( "subtract 20a and 2b from both sides of this equation to get 10b - 2b + a - 20a = -20.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "simplify this to get 8b - 19a = -20.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "from a + b = 11, solve for a to get a = 11 - b. \n" ); document.write( "replace a with 11 - b in the equation of 8b - 19a = -20 to get 8b - 19 * (11 - b) = -10. \n" ); document.write( "simplify this to get 8b - 209 + 19b = -20 \n" ); document.write( "combine like terms to get 27b - 209 = -20 \n" ); document.write( "add 209 to both sides of this equation to get 27b = 189. \n" ); document.write( "divide both sides of this equation by 27 to get b = 189/27 = 7\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "you have b = 7. \n" ); document.write( "since a + b = 11, this means that a = 4.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "your original number is ab = 47. \n" ); document.write( "when you reverse the digits, you get ba = 74.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "your original statement says that when the numbers are reversed, the new number is 20 less than twice the original.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "this means that 74 is equal to 20 less than 2 * 47. \n" ); document.write( "2 * 47 = 94. \n" ); document.write( "94 - 20 = 74. \n" ); document.write( "74 is equal to 74, confirming that the solution is correct.\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( " |