document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=610796>Question 610796</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Four fair coins are flipped. What is the probability of getting three or more heads? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #384690 by </B><A HREF=/tutors/aboutme.mpl?userid=richard1234><B>richard1234(7193)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=richard1234><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=richard1234><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=384690\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> We could use a binomcdf but this is very easy to do by hand.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "P(4 heads) is simply (1/2)^4 = 1/16.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "P(3 heads) is (4C3)(1/2)^4 = 1/4.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "Therefore P(3 or more heads) is equal to 1/4 + 1/16, or 5/16. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );