document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=124817>Question 124817</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Hi. I need some help with the following problem. Thanks\r<BR>\n" );
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document.write( "Use the given information to find the constant of proportionality.<BR>\n" );
document.write( "S varies jointly as p and q. If p = 3 and q = 7, then S = -21.\r<BR>\n" );
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document.write( "k =  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #91606 by </B><A HREF=/tutors/aboutme.mpl?userid=bucky><B>bucky(2189)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=bucky><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=91606\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Saying that S varies jointly as p and q means that S is related to the product of p and q as in:<BR>\n" );
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document.write( "S = k*p*q<BR>\n" );
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document.write( "in which k represents the constant of proportionality.<BR>\n" );
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document.write( "You are given that when p = 3 and q = 7, then S = -21. You can use these values to find the<BR>\n" );
document.write( "value of k. Substitute 3 for p and 7 for q and -21 for S to get:<BR>\n" );
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document.write( "-21 = k*3*7<BR>\n" );
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document.write( "Multiply out the right side to get:<BR>\n" );
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document.write( "-21 = k*21<BR>\n" );
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document.write( "Divide both sides by 21 ... the multiplier of k ... to get:<BR>\n" );
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document.write( "-21/21 = k<BR>\n" );
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document.write( "This simplifies to <BR>\n" );
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document.write( "k = -1<BR>\n" );
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document.write( "Now return to the original joint variation equation of:<BR>\n" );
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document.write( "S = k*p*q<BR>\n" );
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document.write( "substitute -1 for k and you have the joint variation equation as being:<BR>\n" );
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document.write( "S = -1*p*q = -pq<BR>\n" );
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document.write( "So that is the answer to this problem ... k = -1 and as additional information you have  the<BR>\n" );
document.write( "additional knowledge that the equation for S is S = -pq<BR>\n" );
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document.write( "Hope this helps you to understand the problem.<BR>\n" );
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