document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=374065>Question 374065</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Box 1 contains 1000 bulbs of which 10% are defective. Box 2 contains 2000 bulbs of which 5% are defective. Two bulbs are picked from a randomly selected box.<BR>\n" );
document.write( "(a) Find the probability that both bulbs are defective.<BR>\n" );
document.write( "(b) Assuming that both are defective, find the probability that they came from box 1. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #266240 by </B><A HREF=/tutors/aboutme.mpl?userid=edjones><B>edjones(8007)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=edjones><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=edjones><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=266240\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> a)<BR>\n" );
document.write( "There is a 0.5 probability that Box 1 is selected: 100/1000 * 99/999 = .00991<BR>\n" );
document.write( "There is a 0.5 probability that Box 2 is selected: 100/2000 * 99/1999 = .00248<BR>\n" );
document.write( ".<BR>\n" );
document.write( "b)<BR>\n" );
document.write( ".00991/(.00991+.00248)<BR>\n" );
document.write( "=.00991/.01239 (rounding error)<BR>\n" );
document.write( "=.800 the probability that they came from box 1.<BR>\n" );
document.write( ".<BR>\n" );
document.write( "Ed </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );