document.write( "Question 92711: A 2 digit numberis 6 less than 4 times the sum of its digits. If digits are interchange, the new number is 5 less than 8 times the sum of its digits. What's the original number? \n" ); document.write( "
Algebra.Com's Answer #67486 by stanbon(75887)![]() ![]() ![]() You can put this solution on YOUR website! A 2 digit numberis 6 less than 4 times the sum of its digits. If digits are interchange, the new number is 5 less than 8 times the sum of its digits. What's the original number? \n" ); document.write( "-------------- \n" ); document.write( "Comment: Any two digit number can be written as 10t+u where t is the ten's \n" ); document.write( "digit and u is the unit's digit. \n" ); document.write( "------------------ \n" ); document.write( "EQUATIONS: \n" ); document.write( "10t+u+6 = 4(t+u) \n" ); document.write( "10u+t+5 = 8(t+u) \n" ); document.write( "--------------------- \n" ); document.write( "Simplify each equation to get: \n" ); document.write( "6t-3u=-6 \n" ); document.write( "7t-2u= 5 \n" ); document.write( "------------- \n" ); document.write( "Multiply thru the 1st by 2; Multiply thru the 2nd by 3 \n" ); document.write( "---------- \n" ); document.write( "12t-6u = -12 \n" ); document.write( "21t-6u = 15 \n" ); document.write( "--------------- \n" ); document.write( "Subtract the 1st from the 2nd to get: \n" ); document.write( "9t = 27 \n" ); document.write( "t = 3 \n" ); document.write( "----------- \n" ); document.write( "Substitute into 6t-3u=-6 to solve for u: \n" ); document.write( "18 - 3u = -6 \n" ); document.write( "3u = 24 \n" ); document.write( "u = 8 \n" ); document.write( "--------------- \n" ); document.write( "the original number is 38 \n" ); document.write( "================================ \n" ); document.write( "Cheers, \n" ); document.write( "Stan H.\r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |