document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1025898>Question 1025898</A>: <I><SPAN STYLE=\"word-break: break-all;\"> In a box there are R red pens and B blue pens. Pens are randomly selected, one at a time, until a red one is obtained. Assume that each selected pen is replaced before the next one is drawn. (a) what is the probability that you need to pick up a pen 3 times? (b) what is the probability that you need to pick up a pen at least 4 times? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #641259 by </B><A HREF=/tutors/aboutme.mpl?userid=Fombitz><B>Fombitz(32388)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Fombitz><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=Fombitz><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=641259\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> So find the probability that you get BBR.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=P=%28B%2F%28R%2BB%29%29%28B%2F%28R%2BB%29%29%28R%2F%28R%2BB%29%29=%28B%5E2%2AR%29%2F%28B%2BR%29%5E3 ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( ".<BR>\n" );
document.write( ".<BR>\n" );
document.write( ".<BR>\n" );
document.write( "BBBR<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=P=%28B%2F%28R%2BB%29%29%28B%2F%28R%2BB%29%29%28B%2F%28R%2BB%29%29%28R%2F%28R%2BB%29%29=%28B%5E3%2AR%29%2F%28B%2BR%29%5E4 ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" > </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );