document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1025545>Question 1025545</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A hat contains 25 coins - 7 gold, 6 silver and 12 copper.  We randomly select two coins from the hat without replacement.\r<BR>\n" );
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document.write( "a) Let X be the number of gold coins selected.  Find the probability distribution of X.\r<BR>\n" );
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document.write( "b) What is the probability that X = 1 if no silver coins are selected?  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #640815 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><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=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=640815\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> General case:<BR>\n" );
document.write( "first coin is<BR>\n" );
document.write( "gold: 7/25, silver 6/25, copper 12/25.<BR>\n" );
document.write( "second coin<BR>\n" );
document.write( "if first gold, second coin is gold (6/24), silver (6/24), copper (12/24).<BR>\n" );
document.write( "if first silver, second is gold (7/24), silver (5/24), copper (12/24)<BR>\n" );
document.write( "if first copper, second is gold (7/24), silver (6/24) copper (11/24).<BR>\n" );
document.write( "Make a tree diagram<BR>\n" );
document.write( "GG=42/600<BR>\n" );
document.write( "GS=42/600<BR>\n" );
document.write( "GC=84/600<BR>\n" );
document.write( "SG=42/600<BR>\n" );
document.write( "SS=30/600<BR>\n" );
document.write( "SC=72/600<BR>\n" );
document.write( "CG=84/600<BR>\n" );
document.write( "CS=72/600<BR>\n" );
document.write( "CC=132/600<BR>\n" );
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document.write( "Probability of 1 gold with no silver<BR>\n" );
document.write( "GG=42/600NO<BR>\n" );
document.write( "GS=42/600NO<BR>\n" );
document.write( "GC=84/600YES<BR>\n" );
document.write( "SG=42/600NO<BR>\n" );
document.write( "SS=30/600NO<BR>\n" );
document.write( "SC=72/600NO<BR>\n" );
document.write( "CG=84/600YES<BR>\n" );
document.write( "CS=72/600NO<BR>\n" );
document.write( "CC=132/600NO<BR>\n" );
document.write( "The probability is only GC or CG, and that is 168/600 or 7/25. </SPAN>\n" );
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