document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=194383>Question 194383</A>: <I><SPAN STYLE=\"word-break: break-all;\"> i don't know if you can really help me with this but i'll give it a go anyway...<BR>\n" );
document.write( "Records show that the probability is 0.60 that a stolen car in a certain suburb of NSW will be recovered within one week. <BR>\n" );
document.write( "(a) Find the probability that at least 7 of the 10 stolen cars will be recovered.<BR>\n" );
document.write( "(b)Write down an expression for the exact probability that 15 of the 25 stolen cars will be recovered and use it to find this probability to 4 decimal places.\r<BR>\n" );
document.write( "\n" );
document.write( "For (a), i got two answers from 2 attempts: 0.43670016 and 0.3823. I have no idea how to do (b).<BR>\n" );
document.write( "HELP!!! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #145867 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=145867\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> a)<BR>\n" );
document.write( "Let x=.6 and y=.4 (not recovered within 1 week)<BR>\n" );
document.write( "Now we expand the binomial (x+y)^10 an take the 1st four terms:<BR>\n" );
document.write( "x^10=.0060<BR>\n" );
document.write( "10x^9y=.0403<BR>\n" );
document.write( "45x^8y^2=.1209<BR>\n" );
document.write( "120x^7y^3=.2150<BR>\n" );
document.write( "Sum of probabilities: .3823<BR>\n" );
document.write( ".<BR>\n" );
document.write( "b)<BR>\n" );
document.write( "nCr best to find the number in front of the 15th term.<BR>\n" );
document.write( "25C15=3268760<BR>\n" );
document.write( "3268760x^15y^10=.1612<BR>\n" );
document.write( ".<BR>\n" );
document.write( "Ed </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );