document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1163157>Question 1163157</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Your Sock drawer has six white socks, six brown socks, and for black socks. You randomly pick two socks and get a matching pair of black socks. Find the probability of this occurring. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #787156 by </B><A HREF=/tutors/aboutme.mpl?userid=greenestamps><B>greenestamps(13200)</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=787156\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <br><BR>\n" );
document.write( "Tutor @ikleyn showed an elementary way to solve this kind of problem, by looking at the probability of picking two black socks one at a time.<br><BR>\n" );
document.write( "You should know and understand that method for solving the problem.<br><BR>\n" );
document.write( "For more complex problems, a more sophisticated solution method might be required.  You should know that other method, demonstrated below, for solving this problem.<br><BR>\n" );
document.write( "You are choosing 2 socks out of a drawer containing 16 socks.  The number of ways you can do that is \"16 choose 2\": <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=C%2816%2C2%29+=+%28%2816%29%2815%29%29%2F%28%282%29%281%29%29+=+120. ALIGN=MIDDLE  ALT=\"C%2816%2C2%29+=+%28%2816%29%2815%29%29%2F%28%282%29%281%29%29+=+120.\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "The outcome you want is choosing 2 of the 4 black socks.  The number of ways you can do that is \"4 choose 2\": <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=C%284%2C2%29+=+%28%284%29%283%29%29%2F%28%282%29%281%29%29+=+6. ALIGN=MIDDLE  ALT=\"C%284%2C2%29+=+%28%284%29%283%29%29%2F%28%282%29%281%29%29+=+6.\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "The probability that you get 2 black socks is then<br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=C%284%2C2%29%2FC%2816%2C2%29+=+6%2F120+=+1%2F20 ALIGN=MIDDLE  ALT=\"C%284%2C2%29%2FC%2816%2C2%29+=+6%2F120+=+1%2F20\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "Often, in more complicated problems, it is helpful to be more complete in describing the desired outcome.  For this problem, the desired outcome is choosing 2 of the 4 black socks, AND choosing 0 of the 6 white socks, AND 0 of the 6 brown socks.  Then the calculation of the probability of getting 2 black socks is<br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28C%284%2C2%29%2AC%286%2C0%29%2AC%286%2C0%29%29%2FC%2816%2C2%29+=+%286%2A1%2A1%29%2F120+=+1%2F20 ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( " </SPAN>\n" );
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