document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=886073>Question 886073</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Please help me solve this problem:\r<BR>\n" );
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document.write( "A 2-digit number is twice the difference of its digits. What is the number? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #535631 by </B><A HREF=/tutors/aboutme.mpl?userid=Edwin+McCravy><B>Edwin McCravy(20056)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Edwin+McCravy><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=Edwin+McCravy><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=535631\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <PRE STYLE=\"white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;\">\r\n" );
document.write( "Let t = the tens digit\r\n" );
document.write( "Let u = the units digit.\r\n" );
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document.write( "Then the number = 10t+u\r\n" );
document.write( "The difference of digits is t-u\r\n" );
document.write( "Twice the difference of digits = 2(t-u)\r\n" );
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document.write( "We want cases of\r\n" );
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document.write( "10t+u = 2(t-u)\r\n" );
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document.write( "10t+u = 2t-2u\r\n" );
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document.write( "8t+3u = 0\r\n" );
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document.write( "That certainly is not possible.\r\n" );
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document.write( "Perhaps you mean to subtract them the other way u-t\r\n" );
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document.write( "10t+u = 2(u-t)\r\n" );
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document.write( "10t+u = 2u-2t\r\n" );
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document.write( "  12t = u \r\n" );
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document.write( "That's certainly not possible, either\r\n" );
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document.write( "Here is a computer-generated list to show that there is no \r\n" );
document.write( "such two-digit number:\r\n" );
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document.write( "Twice the difference of digits of 10 is 2(1-0) = 2 not 10\r\n" );
document.write( "Twice the difference of digits of 11 is 2(1-1) = 0 not 11\r\n" );
document.write( "Twice the difference of digits of 12 is 2(1-2) = -2 not 12\r\n" );
document.write( "Twice the difference of digits of 13 is 2(1-3) = -4 not 13\r\n" );
document.write( "Twice the difference of digits of 14 is 2(1-4) = -6 not 14\r\n" );
document.write( "Twice the difference of digits of 15 is 2(1-5) = -8 not 15\r\n" );
document.write( "Twice the difference of digits of 16 is 2(1-6) = -10 not 16\r\n" );
document.write( "Twice the difference of digits of 17 is 2(1-7) = -12 not 17\r\n" );
document.write( "Twice the difference of digits of 18 is 2(1-8) = -14 not 18\r\n" );
document.write( "Twice the difference of digits of 19 is 2(1-9) = -16 not 19\r\n" );
document.write( "Twice the difference of digits of 20 is 2(2-0) = 4 not 20\r\n" );
document.write( "Twice the difference of digits of 21 is 2(2-1) = 2 not 21\r\n" );
document.write( "Twice the difference of digits of 22 is 2(2-2) = 0 not 22\r\n" );
document.write( "Twice the difference of digits of 23 is 2(2-3) = -2 not 23\r\n" );
document.write( "Twice the difference of digits of 24 is 2(2-4) = -4 not 24\r\n" );
document.write( "Twice the difference of digits of 25 is 2(2-5) = -6 not 25\r\n" );
document.write( "Twice the difference of digits of 26 is 2(2-6) = -8 not 26\r\n" );
document.write( "Twice the difference of digits of 27 is 2(2-7) = -10 not 27\r\n" );
document.write( "Twice the difference of digits of 28 is 2(2-8) = -12 not 28\r\n" );
document.write( "Twice the difference of digits of 29 is 2(2-9) = -14 not 29\r\n" );
document.write( "Twice the difference of digits of 30 is 2(3-0) = 6 not 30\r\n" );
document.write( "Twice the difference of digits of 31 is 2(3-1) = 4 not 31\r\n" );
document.write( "Twice the difference of digits of 32 is 2(3-2) = 2 not 32\r\n" );
document.write( "Twice the difference of digits of 33 is 2(3-3) = 0 not 33\r\n" );
document.write( "Twice the difference of digits of 34 is 2(3-4) = -2 not 34\r\n" );
document.write( "Twice the difference of digits of 35 is 2(3-5) = -4 not 35\r\n" );
document.write( "Twice the difference of digits of 36 is 2(3-6) = -6 not 36\r\n" );
document.write( "Twice the difference of digits of 37 is 2(3-7) = -8 not 37\r\n" );
document.write( "Twice the difference of digits of 38 is 2(3-8) = -10 not 38\r\n" );
document.write( "Twice the difference of digits of 39 is 2(3-9) = -12 not 39\r\n" );
document.write( "Twice the difference of digits of 40 is 2(4-0) = 8 not 40\r\n" );
document.write( "Twice the difference of digits of 41 is 2(4-1) = 6 not 41\r\n" );
document.write( "Twice the difference of digits of 42 is 2(4-2) = 4 not 42\r\n" );
document.write( "Twice the difference of digits of 43 is 2(4-3) = 2 not 43\r\n" );
document.write( "Twice the difference of digits of 44 is 2(4-4) = 0 not 44\r\n" );
document.write( "Twice the difference of digits of 45 is 2(4-5) = -2 not 45\r\n" );
document.write( "Twice the difference of digits of 46 is 2(4-6) = -4 not 46\r\n" );
document.write( "Twice the difference of digits of 47 is 2(4-7) = -6 not 47\r\n" );
document.write( "Twice the difference of digits of 48 is 2(4-8) = -8 not 48\r\n" );
document.write( "Twice the difference of digits of 49 is 2(4-9) = -10 not 49\r\n" );
document.write( "Twice the difference of digits of 50 is 2(5-0) = 10 not 50\r\n" );
document.write( "Twice the difference of digits of 51 is 2(5-1) = 8 not 51\r\n" );
document.write( "Twice the difference of digits of 52 is 2(5-2) = 6 not 52\r\n" );
document.write( "Twice the difference of digits of 53 is 2(5-3) = 4 not 53\r\n" );
document.write( "Twice the difference of digits of 54 is 2(5-4) = 2 not 54\r\n" );
document.write( "Twice the difference of digits of 55 is 2(5-5) = 0 not 55\r\n" );
document.write( "Twice the difference of digits of 56 is 2(5-6) = -2 not 56\r\n" );
document.write( "Twice the difference of digits of 57 is 2(5-7) = -4 not 57\r\n" );
document.write( "Twice the difference of digits of 58 is 2(5-8) = -6 not 58\r\n" );
document.write( "Twice the difference of digits of 59 is 2(5-9) = -8 not 59\r\n" );
document.write( "Twice the difference of digits of 60 is 2(6-0) = 12 not 60\r\n" );
document.write( "Twice the difference of digits of 61 is 2(6-1) = 10 not 61\r\n" );
document.write( "Twice the difference of digits of 62 is 2(6-2) = 8 not 62\r\n" );
document.write( "Twice the difference of digits of 63 is 2(6-3) = 6 not 63\r\n" );
document.write( "Twice the difference of digits of 64 is 2(6-4) = 4 not 64\r\n" );
document.write( "Twice the difference of digits of 65 is 2(6-5) = 2 not 65\r\n" );
document.write( "Twice the difference of digits of 66 is 2(6-6) = 0 not 66\r\n" );
document.write( "Twice the difference of digits of 67 is 2(6-7) = -2 not 67\r\n" );
document.write( "Twice the difference of digits of 68 is 2(6-8) = -4 not 68\r\n" );
document.write( "Twice the difference of digits of 69 is 2(6-9) = -6 not 69\r\n" );
document.write( "Twice the difference of digits of 70 is 2(7-0) = 14 not 70\r\n" );
document.write( "Twice the difference of digits of 71 is 2(7-1) = 12 not 71\r\n" );
document.write( "Twice the difference of digits of 72 is 2(7-2) = 10 not 72\r\n" );
document.write( "Twice the difference of digits of 73 is 2(7-3) = 8 not 73\r\n" );
document.write( "Twice the difference of digits of 74 is 2(7-4) = 6 not 74\r\n" );
document.write( "Twice the difference of digits of 75 is 2(7-5) = 4 not 75\r\n" );
document.write( "Twice the difference of digits of 76 is 2(7-6) = 2 not 76\r\n" );
document.write( "Twice the difference of digits of 77 is 2(7-7) = 0 not 77\r\n" );
document.write( "Twice the difference of digits of 78 is 2(7-8) = -2 not 78\r\n" );
document.write( "Twice the difference of digits of 79 is 2(7-9) = -4 not 79\r\n" );
document.write( "Twice the difference of digits of 80 is 2(8-0) = 16 not 80\r\n" );
document.write( "Twice the difference of digits of 81 is 2(8-1) = 14 not 81\r\n" );
document.write( "Twice the difference of digits of 82 is 2(8-2) = 12 not 82\r\n" );
document.write( "Twice the difference of digits of 83 is 2(8-3) = 10 not 83\r\n" );
document.write( "Twice the difference of digits of 84 is 2(8-4) = 8 not 84\r\n" );
document.write( "Twice the difference of digits of 85 is 2(8-5) = 6 not 85\r\n" );
document.write( "Twice the difference of digits of 86 is 2(8-6) = 4 not 86\r\n" );
document.write( "Twice the difference of digits of 87 is 2(8-7) = 2 not 87\r\n" );
document.write( "Twice the difference of digits of 88 is 2(8-8) = 0 not 88\r\n" );
document.write( "Twice the difference of digits of 89 is 2(8-9) = -2 not 89\r\n" );
document.write( "Twice the difference of digits of 90 is 2(9-0) = 18 not 90\r\n" );
document.write( "Twice the difference of digits of 91 is 2(9-1) = 16 not 91\r\n" );
document.write( "Twice the difference of digits of 92 is 2(9-2) = 14 not 92\r\n" );
document.write( "Twice the difference of digits of 93 is 2(9-3) = 12 not 93\r\n" );
document.write( "Twice the difference of digits of 94 is 2(9-4) = 10 not 94\r\n" );
document.write( "Twice the difference of digits of 95 is 2(9-5) = 8 not 95\r\n" );
document.write( "Twice the difference of digits of 96 is 2(9-6) = 6 not 96\r\n" );
document.write( "Twice the difference of digits of 97 is 2(9-7) = 4 not 97\r\n" );
document.write( "Twice the difference of digits of 98 is 2(9-8) = 2 not 98\r\n" );
document.write( "Twice the difference of digits of 99 is 2(9-9) = 0 not 99\r\n" );
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document.write( "Edwin</PRE> </SPAN>\n" );
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