document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=425915>Question 425915</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Hello,<BR>\n" );
document.write( "Any help is much appreciated, having a hard time wrapping my head around probability. <BR>\n" );
document.write( "Question:<BR>\n" );
document.write( "Armco, a manufacturer of traffic light systems found that under accelerated life tests 95% of the newly developed systems lasted 3 years before failing to change signals properly.<BR>\n" );
document.write( "a)If a city purchases 4 of these systems, what is the probability that all 4 systems would operate properly for at least 3 years?<BR>\n" );
document.write( "b)Which rule of probability does this illustrate?<BR>\n" );
document.write( "c)using letters to represent the four systems, write an equation to show how you arrived to the answer to part a. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #296400 by </B><A HREF=/tutors/aboutme.mpl?userid=Theo><B>Theo(13342)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Theo><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=Theo><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=296400\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> probability of 1 system lasting 3 years before failing is .95\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "probability of all 4 systems lasting 3 years is .95*.95*.95*.95 = .81450625.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "the formula that applies is p(a intersect b) otherwise known as p(a and b)\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "p(a intersect b) or p(a and b) equals p(a) * p(b)\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );