document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=74040>Question 74040</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Please help me to explain how to solve this problem..thanks<BR>\n" );
document.write( "3 electric lamps are to be fitted in a room.  3 bulbs are chosen at random from 10 bulbs out of which 6 work.  What is the chance the room will be lighted?\r<BR>\n" );
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document.write( "this was a problem on a worksheet. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #53096 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=53096\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 3 electric lamps are to be fitted in a room. 3 bulbs are chosen at random from 10 bulbs out of which 6 work. What is the chance the room will be lighted? <BR>\n" );
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document.write( "I assume the room will be lighted if at least one of the 3 bulbs selected<BR>\n" );
document.write( "is not defective.<BR>\n" );
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document.write( "There are 4C3= 4 groups of bulbs that are all defective<BR>\n" );
document.write( "There are 10C3 = 120 total number of groups of 3.<BR>\n" );
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document.write( "The probability of selecting a group that has at least<BR>\n" );
document.write( "one non-defective bulb is 116/120 = 0.966666...<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
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