document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=38712>Question 38712</A>: <I><SPAN STYLE=\"word-break: break-all;\"> 1) There are four letters and four envelopes. If the letters are placed in the <BR>\n" );
document.write( "envelopes at random, what is the probability that not more than one letter is placed in the correct envelope?\r<BR>\n" );
document.write( "\n" );
document.write( "2) The equation of regression lines are<BR>\n" );
document.write( "     3x+12y=19<BR>\n" );
document.write( "     3y+9x=46<BR>\n" );
document.write( "Find 1) Correlation co- efficient<BR>\n" );
document.write( "         2) Mean value of X and Y<BR>\n" );
document.write( "         3) Ratio of the co- efficient of variability of X to Y </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #28642 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=28642\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> ) There are four letters and four envelopes. If the letters are placed in the <BR>\n" );
document.write( "envelopes at random, what is the probability that not more than one letter is placed in the correct envelope?\r<BR>\n" );
document.write( "\n" );
document.write( "Probability that a letter is placed in the correct envelope = 1/4<BR>\n" );
document.write( "Prob that \"not more than one letter is correctly placed\" means <BR>\n" );
document.write( "0 or 1 are correctly placed.<BR>\n" );
document.write( "Prob (0 are correctly placed) = (3/4)^4=0.3164<BR>\n" );
document.write( "Prob (1 is correctly placed) = 4C1 (1/4)(3/4)^3=0.421875\r<BR>\n" );
document.write( "\n" );
document.write( "Sine there are mutually exclusive events you add the probabilities<BR>\n" );
document.write( "to get 0.73828125\r<BR>\n" );
document.write( "\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );