document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=165671>Question 165671</A>: <I><SPAN STYLE=\"word-break: break-all;\"> calculate the probabilty of randomly guessing the given number of correct answers on a 30-question multiple-choice exam that has choices A, B,C,and D for each question. \r<BR>\n" );
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document.write( "#19) 2 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #122134 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=122134\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The chance of guessing exactly 2 answers correctly out of 30 questions.<BR>\n" );
document.write( "Let b=1/4, the chance of guessing a question correctly and a=3/4, guessing it wrong.<BR>\n" );
document.write( "The coefficient of a^28b^2 is nCr=30C2=435<BR>\n" );
document.write( "435*(3/4)^28*(1/4)^2=.008631...<BR>\n" );
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document.write( "Ed </SPAN>\n" );
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