document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=475183>Question 475183</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Dear math teacher, \r<BR>\n" );
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document.write( "I am not sure why I am having a pretty hard time with combinations.  I really nailed the Permutations section of the chapter but the combinations are not that nice to me. \r<BR>\n" );
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document.write( "Here is the problem I am struggling with: <BR>\n" );
document.write( "\"A has 3 maps and B has 9 maps.  Determine the number of ways in which they can exchange maps if each keeps his initial number of maps. \"\r<BR>\n" );
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document.write( "Here is what I did:  12C3 + 12C9 = 220 + 220 = 440 but that is not the right answer.  Thank you for your time and help. \r<BR>\n" );
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document.write( "Yours respectfully, \r<BR>\n" );
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document.write( "I.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #325818 by </B><A HREF=/tutors/aboutme.mpl?userid=scott8148><B>scott8148(6628)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=scott8148><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=scott8148><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=325818\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> there are 3 ways that A can give B one map, and 9 ways that B can give A one map<BR>\n" );
document.write( "___ 27 ways they can exchange ONE map ___ (3C1) * (9C1)\r<BR>\n" );
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document.write( "for TWO maps ___ (3C2) * (9C2)\r<BR>\n" );
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document.write( "for THREE maps ...\r<BR>\n" );
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document.write( "add the three results </SPAN>\n" );
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