document.write( "Question 840588: how many two digit numbers with their tens digit greater than their unit digit,have the sum of their digits equal to twice their differrence? \n" ); document.write( "

Algebra.Com's Answer #506365 by Edwin McCravy(20055) $\"\"$ $\"About$

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tens digit greater than their unit digit
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t>u

the sum of their digits equal to twice their difference

t+u = 2(t-u)\r\n" );
document.write( "t+u = 2t-2u\r\n" );
document.write( " 3u = t \r\n" );
document.write( "So the system is:\r\n" );
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document.write( "Since 1 ≦ t ≦ 9\r\n" );
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document.write( "      1 ≦ 3u ≦ 9\r\n" );
document.write( "     1/3 ≦ u ≦ 3\r\n" );
document.write( "       1 ≦ u ≦ 3\r\n" );
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document.write( "So u = 1, 2 or 3\r\n" );
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document.write( "If u = 1, then t = 3u = 3(1) = 3, so the number is 31\r\n" );
document.write( "If u = 2, then t = 3u = 3(2) = 6, so the number is 62\r\n" );
document.write( "If u = 3, then t = 3u = 3(3) = 9, so the number is 93\r\n" );
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document.write( "So there are three solutions: 31, 62, and 93\r\n" );
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document.write( "Edwin

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