document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1026474>Question 1026474</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Use the pattern in Pascal's triangle to find the probability of getting 2 heads when four fair coins are tossed. (type an integer or a simplified fraction) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #641716 by </B><A HREF=/tutors/aboutme.mpl?userid=Timnewman><B>Timnewman(323)</B></A><img src=\"/images/stars/stars-10.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Timnewman><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=Timnewman><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=641716\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> lets follow your question up by expansion as suggested by pascal using pascals triangle.<BR>\n" );
document.write( " In a coin,we have tail (T) and head (H).<BR>\n" );
document.write( "Therefore a coin =(H+T)<BR>\n" );
document.write( "since there are four coin here,we raise (H+T) to power of 4<BR>\n" );
document.write( "That is,(H+T)^4<BR>\n" );
document.write( "Expand the above,we have<BR>\n" );
document.write( "(H+T)^4=H^4+4H^3T+6H²T²<BR>\n" );
document.write( "           +HT^3+H^4<BR>\n" );
document.write( "Two head lies on 6H²T²<BR>\n" );
document.write( "but p(H)=1/2 also, p(T)=1/2<BR>\n" );
document.write( "Therefore,<BR>\n" );
document.write( "p(two head)=p(6H²T²)<BR>\n" );
document.write( "              =6(1/2)²(1/2)²<BR>\n" );
document.write( "  =6(1/4)(1/4)<BR>\n" );
document.write( "  =6(1/16)<BR>\n" );
document.write( "  =6/16<BR>\n" );
document.write( "=3/8<BR>\n" );
document.write( "Hope this helps too? </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );