document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=279490>Question 279490</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The sum of the digits of a two- digit number is 12. If 36 is added to the number, then the number obtained is the original with its digits interchanged. Find the original number. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #854175 by </B><A HREF=/tutors/aboutme.mpl?userid=greenestamps><B>greenestamps(13325)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=greenestamps><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=greenestamps><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=854175\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <br><BR>\n" );
document.write( "Here is a quick mental solution you can use if formal algebra is not required, and if the speed of finding the solution is important -- as in a timed competitive exam.<br><BR>\n" );
document.write( "The difference between a 2-digit number and the number with the digits reversed is 9 times the difference of the two digits.  Since the difference between the two 2-digit numbers is 36, the difference between the two digits is 36/9 = 4.<br><BR>\n" );
document.write( "So the sum of the two digits is 12 and the difference is 4.  Quick mental reasoning shows the digits are 4 and 8.<br><BR>\n" );
document.write( "So the original number is 48 and the number with the digits reversed is 84.<br><BR>\n" );
document.write( "ANSWER: 48<br><BR>\n" );
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