document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=703062>Question 703062</A>: <I><SPAN STYLE=\"word-break: break-all;\">     Guessing on an exam. In a multiple choice exam, there are 5 questions and 4 choices<BR>\n" );
document.write( "    for each question (a, b, c, d). Nancy has not studied for the exam at all and decides to randomly<BR>\n" );
document.write( "    guess the answers. What is the probability that:\r<BR>\n" );
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document.write( "(a) the first question she gets right is the 5th question?\r<BR>\n" );
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document.write( "I have so far, n=5 and p=.25. The \"5th question\" throws me off...<BR>\n" );
document.write( "     </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #433401 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=433401\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Guessing on an exam. In a multiple choice exam, there are 5 questions and 4 choices<BR>\n" );
document.write( "for each question (a, b, c, d). Nancy has not studied for the exam at all and decides to randomly<BR>\n" );
document.write( "guess the answers. What is the probability that: <BR>\n" );
document.write( "(a) the first question she gets right is the 5th question? <BR>\n" );
document.write( "I have so far, n=5 and p=.25. The \"5th question\" throws me off...<BR>\n" );
document.write( "----<BR>\n" );
document.write( "If the 5th is the first correct the answer pattern is wwwwc<BR>\n" );
document.write( "where w is \"wrong\" and c is \"correct\".<BR>\n" );
document.write( "---<BR>\n" );
document.write( "P(wwwwc) = (3/4)^4*(1/4) = 81/1024<BR>\n" );
document.write( "==============<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
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