document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1011009>Question 1011009</A>: <I><SPAN STYLE=\"word-break: break-all;\"> a box contain 50 light bulbs, of which 4 are detective. you purchase two bulbs from this box. what is the probability that both will be defective?  </SPAN>\n" );
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document.write( "Question:<BR>\n" );
document.write( "a box contain 50 light bulbs, of which 4 are detective. you purchase two bulbs from this box. what is the probability that both will be defective? <BR>\n" );
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document.write( "Solution:<BR>\n" );
document.write( "Given 4 out of 50 light bulbs are defective.<BR>\n" );
document.write( "Draw two from the batch.<BR>\n" );
document.write( "Let D=event that light bulb drawn is defective.<BR>\n" );
document.write( "and ~D=event that light bulb drawn is normal.<BR>\n" );
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document.write( "Need to find P(DD)<BR>\n" );
document.write( "Recall that there are 4 defectives out of 50 at the first draw, and 3 defectives out of 49 at the second draw.<BR>\n" );
document.write( "Using the multiplication rule, then<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=P%28DD%29=%284%2F50%29%283%2F49%29=6%2F1225 ALIGN=MIDDLE  ALT=\"P%28DD%29=%284%2F50%29%283%2F49%29=6%2F1225\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( " <BR>\n" );
document.write( "Answer: the probability of drawing two defective light-bulbs is 6/1225 </SPAN>\n" );
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