document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=468918>Question 468918</A>: <I><SPAN STYLE=\"word-break: break-all;\"> What probability rule is this and how to I solve it?\r<BR>\n" );
document.write( "\n" );
document.write( "From a group of 9 people, you randomly select 4 of them.\r<BR>\n" );
document.write( "\n" );
document.write( "What is the probability that they are the 4 oldest people in the group?\r<BR>\n" );
document.write( "\n" );
document.write( "Give your answer as a fraction. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #321767 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=321767\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> From a group of 9 people, you randomly select 4 of them. <BR>\n" );
document.write( "What is the probability that they are the 4 oldest people in the group? <BR>\n" );
document.write( "-------------<BR>\n" );
document.write( "There is only 1 group of the 4 oldest.<BR>\n" );
document.write( "There are 9C4 = (9*8*7*6)/(1*2*3*4) = 126 groups<BR>\n" );
document.write( "---<BR>\n" );
document.write( "P(select the 4 oldest) = 1/126<BR>\n" );
document.write( "------------------<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );