document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=726666>Question 726666</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I have this question on my homework: You put $500 in a savings account. The account earns $15.75 simple interest in 6 months. What is the annual interest rate? I know the formula is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r=I%2FPt ALIGN=MIDDLE  ALT=\"r=I%2FPt\"   DISABLED_style= \"max-width:90%; height:auto;\" > But how do I set the problem up? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #444739 by </B><A HREF=/tutors/aboutme.mpl?userid=KMST><B>KMST(5328)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=KMST><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=KMST><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=444739\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r=I%2FPt ALIGN=MIDDLE  ALT=\"r=I%2FPt\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=I ALIGN=MIDDLE  ALT=\"I\"   DISABLED_style= \"max-width:90%; height:auto;\" >= Interest earned<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=P ALIGN=MIDDLE  ALT=\"P\"   DISABLED_style= \"max-width:90%; height:auto;\" >= Principal (amount deposited)<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t ALIGN=MIDDLE  ALT=\"t\"   DISABLED_style= \"max-width:90%; height:auto;\" >= time (in years, because you want the annual interest rate)<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r ALIGN=MIDDLE  ALT=\"r\"   DISABLED_style= \"max-width:90%; height:auto;\" >= Interest rate (expressed as a decimal)<BR>\n" );
document.write( " <BR>\n" );
document.write( "For your problem<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r=15.75%2F%28500%2A0.5%29 ALIGN=MIDDLE  ALT=\"r=15.75%2F%28500%2A0.5%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > or <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r=15.75%2F%28500%2A%281%2F2%29%29 ALIGN=MIDDLE  ALT=\"r=15.75%2F%28500%2A%281%2F2%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "That is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r=15.75%2F250 ALIGN=MIDDLE  ALT=\"r=15.75%2F250\"   DISABLED_style= \"max-width:90%; height:auto;\" > --> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r=0.063 ALIGN=MIDDLE  ALT=\"r=0.063\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "The annual interest rate is 6.3%.<BR>\n" );
document.write( " <BR>\n" );
document.write( "MENTAL MATH<BR>\n" );
document.write( "If you had left the money in that account for 1 year, you would have earned double the amount you earned in interest.<BR>\n" );
document.write( "If you had been able to deposit twice as much ($1000) and let that money earning interest for 1 year you would have earned 4 times as much as you did.<BR>\n" );
document.write( "15 dollars is 60 quarters, so 15.75 dollars is 63 quarters.<BR>\n" );
document.write( "4 times 63 quarters is 63 dollars.<BR>\n" );
document.write( "$1000 would earn $63 in 1 year, so $100 would earn $6.30 in a year,<BR>\n" );
document.write( "so the annual interest rate is 6.3%.<BR>\n" );
document.write( "I can think through that a lot faster than I can type it. </SPAN>\n" );
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