document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=271633>Question 271633</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Time on a treadmill. After 2 minutes on a treadmill, Jenny has a heart rate of 82. After 3 minutes she has a heart rate of 86. Assume that there is a linear equation that gives her heart rate h in terms of time on the treadmill t. Find the equation and use it to predict her heart rate after 10 minutes on the treadmill. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #198880 by </B><A HREF=/tutors/aboutme.mpl?userid=dabanfield><B>dabanfield(803)</B></A><img src=\"/images/stars/stars-11.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=dabanfield><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=198880\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Time on a treadmill. After 2 minutes on a treadmill, Jenny has a heart rate of 82. After 3 minutes she has a heart rate of 86. Assume that there is a linear equation that gives her heart rate h in terms of time on the treadmill t. Find the equation and use it to predict her heart rate after 10 minutes on the treadmill.\r<BR>\n" );
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document.write( "From the data we know that two points on the line are (2,82) and (3,86). From these two points we can calculate the slope m:\r<BR>\n" );
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document.write( "m = (86-82)/(3-2) <BR>\n" );
document.write( "m = 4/1<BR>\n" );
document.write( "m = 4\r<BR>\n" );
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document.write( "In slope-intercept form our line then is:\r<BR>\n" );
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document.write( "y = m*x + b<BR>\n" );
document.write( "y = 4*x + b\r<BR>\n" );
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document.write( "We still need to find b. Since the point (2,82) is on the line we know that when y = 82, x = 2. So from above we have:\r<BR>\n" );
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document.write( "y = 4*x + b<BR>\n" );
document.write( "82 = 4*2 + b<BR>\n" );
document.write( "82 = 8 + b<BR>\n" );
document.write( "b = 74\r<BR>\n" );
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document.write( "The line then is:\r<BR>\n" );
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document.write( "y = 4x + 74 \r<BR>\n" );
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document.write( "After 10 seconds then we have:\r<BR>\n" );
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document.write( "y = 4*10 + 74<BR>\n" );
document.write( "y = 40 + 74<BR>\n" );
document.write( "y = 114\r<BR>\n" );
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document.write( " </SPAN>\n" );
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