document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=48117>Question 48117</A>This question is from textbook <A HREF=http://www.amazon.com/exec/obidos/ASIN/0534373526/algebrahomeworkh>College Algebra</A><BR>\n" );
document.write( ": <I><SPAN STYLE=\"word-break: break-all;\"> A kettle full of water is brought to a boil in a room with temperature 20C. After 15 minutes the temperature of the water has decreased from 100C to 75C. Find the temperature after another 10 minutes, and sketch a graph of the temperature function.\r<BR>\n" );
document.write( "\n" );
document.write( "Thank you so much! Does this have anything to do with Newton's Law of Cooling and the formula T(t) = Ts + D0e^-kt? My calculator simply will not do this. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #31870 by </B><A HREF=/tutors/aboutme.mpl?userid=cowess><B>cowess(34)</B></A><img src=\"/images/stars/stars-07.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=cowess><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=31870\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 10/15*(100-75)=(2/3)*25=16.67<BR>\n" );
document.write( "75-16.67=58.33\r<BR>\n" );
document.write( "\n" );
document.write( "suppose y is the temperature of the water in the kettle,<BR>\n" );
document.write( "x is the amount of time after the water was boiled.<BR>\n" );
document.write( "So y=100-25(x/15), but the water will stay at room temperature and cease to decrease so when y=20, x=((100-20)/25)*15=(16/5)*15=48<BR>\n" );
document.write( "The line on the graph change directions after x=48<BR>\n" );
document.write( "1)48>=x>=0, y=100-25(x/15)<BR>\n" );
document.write( "2)x>=48, y=20<BR>\n" );
document.write( "         </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );