document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=967414>Question 967414</A>: <I><SPAN STYLE=\"word-break: break-all;\"> In a shipment of 18 smart phones, 2 are defective. How many ways can a quality control inspector randomly test 4 smart phones, of which 2 are defective? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #591273 by </B><A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><B>jim_thompson5910(35256)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><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=591273\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 18 phones total<BR>\n" );
document.write( "16 nondefective<BR>\n" );
document.write( "2 defective\r<BR>\n" );
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document.write( "Testing 4 phones: 2 defective, 2 nondefective\r<BR>\n" );
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document.write( "Number of ways to pick 2 defective phones:\r<BR>\n" );
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document.write( "2 C 2 = (2!)/(2!*(2-2)!) = 1\r<BR>\n" );
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document.write( "I'm using the <a  rel=nofollow HREF=\"http://www.mathwords.com/c/combination_formula.htm\">combination formula</a>.\r<BR>\n" );
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document.write( "There is 1 way to pick 2 defective phones from a pool of 2 total defective phones.\r<BR>\n" );
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document.write( "Number of ways to pick 2 nondefective phones\r<BR>\n" );
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document.write( "16 C 2 = (16!)/(2!*(16-2)!) = 120\r<BR>\n" );
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document.write( "So there are 1*120 = 120 different ways to pick 4 smart phones, of which 2 are defective </SPAN>\n" );
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