document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=3655>Question 3655</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The cost C of manufacturing a certain product can be estimated by the formula C = 0.03rst2, where r and s are the amounts, in pounds, of the two major ingredients and t is the production time in hours. If r is increased by 50 percent, s is increased by 20 percent, and t is decreased by 30 percent, by approximately what percent will the estimated cost of manufacturing the product change?<BR>\n" );
document.write( "(A) 40% increase<BR>\n" );
document.write( "(B) 12% increase<BR>\n" );
document.write( "(C) 4% increase <BR>\n" );
document.write( "(D) 12% decrease </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #1618 by </B><A HREF=/tutors/aboutme.mpl?userid=Zenock><B>Zenock(15)</B></A><img src=\"/images/stars/stars-06.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Zenock><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=1618\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> For the question as written none of the answers are correct.  Therefore I believe the original formula should have read...<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=C=0.03rst%5E2 ALIGN=MIDDLE  ALT=\"C=0.03rst%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Assuming this is correct.\r<BR>\n" );
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document.write( "Lets let d=the percentage of change in cost...\r<BR>\n" );
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document.write( "Then:<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=C%2Bd%2AC=C%281%2Bd%29=0.03%28r%2B.5r%29%28s%2B.2s%29%28t-.3t%29%5E2=0.03%281.5r%29%281.2s%29%28.7t%29%5E2=0.03%2A0.882%28rst%5E2%29 ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=C=0.03rst%5E2 ALIGN=MIDDLE  ALT=\"C=0.03rst%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" > so <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%281%2Bd%29%280.03rst%5E2%29=0.03%2A0.882%28rst%5E2%29 ALIGN=MIDDLE  ALT=\"%281%2Bd%29%280.03rst%5E2%29=0.03%2A0.882%28rst%5E2%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "So: <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1%2Bd=0.882 ALIGN=MIDDLE  ALT=\"1%2Bd=0.882\"   DISABLED_style= \"max-width:90%; height:auto;\" > so <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d=-0.118 ALIGN=MIDDLE  ALT=\"d=-0.118\"   DISABLED_style= \"max-width:90%; height:auto;\" > which is approximately -12%.  \r<BR>\n" );
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document.write( "The answer is (D) 12% decrease </SPAN>\n" );
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