document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1166717>Question 1166717</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A theatre has 20 rows of chairs . The first row has 16 chairs , the second has 18, the third has 20 , and so on . In total , the theatre seats how many people?  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #791224 by </B><A HREF=/tutors/aboutme.mpl?userid=dkppathak><B>dkppathak(439)</B></A><img src=\"/images/stars/stars-10.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=dkppathak><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=dkppathak><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=791224\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A theatre has 20 rows of chairs . The first row has 16 chairs , the second has 18, the third has 20 , and so on . In total , the theatre seats how many people?<BR>\n" );
document.write( "solution <BR>\n" );
document.write( "16,+18,+20.+...............+.20th <BR>\n" );
document.write( "this is problem of sum of AP<BR>\n" );
document.write( "a=16 d=2   n=20  we have to find s20=?<BR>\n" );
document.write( " a20=a+19d <BR>\n" );
document.write( "l (last term)=16+19x2<BR>\n" );
document.write( "=16+38=54<BR>\n" );
document.write( "sn=n(a+l)/2=20(16+54)/2<BR>\n" );
document.write( "s20=20x70/2=700<BR>\n" );
document.write( "total 700  seats  </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );