document.write( "Question 387213: a two digit number is 11 times its units digit. The sum of the digits is 12. find the number \n" ); document.write( "
Algebra.Com's Answer #276078 by gwendolyn(128)![]() ![]() You can put this solution on YOUR website! Let X be the tens digit \n" ); document.write( "Let Y be the units digit\r \n" ); document.write( "\n" ); document.write( "The value of the two digit number is calculated as 10*X + Y, since X is the digit in the tens spot. Since this number is 11 times its units digit, then\r \n" ); document.write( "\n" ); document.write( "10*X + Y = 11*Y \n" ); document.write( "Subtract Y from both sides: \n" ); document.write( "10*X + Y - Y = 11*Y - Y \n" ); document.write( "10*X = 10*Y \n" ); document.write( "Divide both sides by 10: \n" ); document.write( " \n" ); document.write( "X = Y \n" ); document.write( "(Which makes sense if you think about two-digit multiples of 11.)\r \n" ); document.write( "\n" ); document.write( "The sum of the digits is 12, so: \n" ); document.write( "X + Y = 12\r \n" ); document.write( "\n" ); document.write( "Substitute the value of X from the first equation: \n" ); document.write( "Y + Y = 12 \n" ); document.write( "2*Y = 12 \n" ); document.write( "Divide both sides by 2:\r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( "Y = 6 \n" ); document.write( "Substitute in the first equation for X: \n" ); document.write( "X = 6 \n" ); document.write( "So, the two-digit number is 66 \n" ); document.write( " |