document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1105355>Question 1105355</A>: <I><SPAN STYLE=\"word-break: break-all;\">  A cumulative deposit  account of monthly installment of rs. 3600 at 9%  p.a. simple interest earns an interest of rs. 17982. Find the number of installment paid.   </SPAN>\n" );
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document.write( "If the monthly deposit amount is rs. 3600 and the interest is simple interest at 9% per year, then the amount of interest on each deposit each month is<BR>\n" );
document.write( "rs. 3600*(.09/12) = rs. 27<br><BR>\n" );
document.write( "If n is the number of deposits that are made, then the total amount of interest earned on the first deposit is 27(n); the total amount of interest on the second deposit is 27(n-1);...; the total amount of interest on the next-to-last deposit is 27(2), and the total amount of interest on the last deposit is 27(1).<br><BR>\n" );
document.write( "Then the total amount of interest on all the deposits is<BR>\n" );
document.write( "27(n+(n-1)+...+2+1) = 27*((n(n+1)/2)<br><BR>\n" );
document.write( "Since the total amount of interest is rs. 17982,<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=27%28n%28n%2B1%29%2F2%29+=+17982 ALIGN=MIDDLE  ALT=\"27%28n%28n%2B1%29%2F2%29+=+17982\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n%28n%2B1%29+=+2%2A17982%2F27+=+1332 ALIGN=MIDDLE  ALT=\"n%28n%2B1%29+=+2%2A17982%2F27+=+1332\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "Any of various methods will lead to <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=36%2A37=1332 ALIGN=MIDDLE  ALT=\"36%2A37=1332\"   DISABLED_style= \"max-width:90%; height:auto;\" >, so the number of deposits n is 36.<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );