document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=223142>Question 223142</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Suppose that the credit remaining on a phone card (in dollars) is a linear function of the total calling time (in minutes). When graphed, the function gives a line with a slope of -0.16 <BR>\n" );
document.write( "There is $29.00 in credit remaining on the card after 25 minutes of calls. How much credit was there after 18 minutes of calls? \r<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #166906 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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=166906\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Suppose that the credit remaining on a phone card (in dollars) is a linear function of the total calling time (in minutes). When graphed, the function gives a line with a slope of -0.16 <BR>\n" );
document.write( "There is $29.00 in credit remaining on the card after 25 minutes of calls. How much credit was there after 18 minutes of calls? <BR>\n" );
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document.write( "Credit Equation: C(x) = -0.16x + r where \"x\" is number of minutes of calls<BR>\n" );
document.write( "29 = -0.16*25 + r<BR>\n" );
document.write( "r = 29+4 dollars<BR>\n" );
document.write( "r = 33 dollars<BR>\n" );
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document.write( "So the Credit Remaining equation is:<BR>\n" );
document.write( "C(x) = -0.16x + 33<BR>\n" );
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document.write( "How much credit was there after 18 minutes of calls? <BR>\n" );
document.write( "C(18) = -0.16*18+33<BR>\n" );
document.write( "C(18) = $30.12<BR>\n" );
document.write( "====================<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
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