document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=149737>Question 149737</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Still struggling with this one. There are 20 customers. 18 will make a purchase. If three customers are selected, one at a time, what is the probability that all will make a purchase? Instructor says the answer is one of four 1)0.7717, 2) 0.7605 3) 0.8524 or 4)0.8808\r<BR>\n" );
document.write( "\n" );
document.write( "Please help </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #109845 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=109845\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> would be interested in seeing the instructor's solution\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "there are 20C3 (1140) possible groups of 3 in 20 __ some of these groups contain non-purchasers\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "there are 18C3 (816) possible groups of 3 in 18 __ none of these groups contain non-purchasers\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "probability of all purchasers is 816/1140 or 0.716 (approx)\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "if order of selection is thought to be important (permutation vs combination); the result will be the same </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );