document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=407537>Question 407537</A>: <I><SPAN STYLE=\"word-break: break-all;\"> in the 1920 the record for a certain race was 46.3 sec. in 1930 it was 46.1sec. let R(t)= the record in the race and t= the number of years since 1920 .\r<BR>\n" );
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document.write( "a)find a linear function that finds the data<BR>\n" );
document.write( "b)use the function in a) to predict the record in 2003 and 2006<BR>\n" );
document.write( "c)find the year when the record will be 44.50 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #287293 by </B><A HREF=/tutors/aboutme.mpl?userid=graphmatics><B>graphmatics(170)</B></A><img src=\"/images/stars/stars-09.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=graphmatics><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/cgi-bin/show-face.mpl?user=graphmatics><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=287293\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The decrease in sec of race speed reduction of t years is, <BR>\n" );
document.write( "f(t) = (46.3-46.1)*(t/10)<BR>\n" );
document.write( "f(t) = 0.2*(t/10)<BR>\n" );
document.write( "f(t) = 0.2*t/10<BR>\n" );
document.write( "f(t) = 0.2*t/10<BR>\n" );
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document.write( "so for 2003<BR>\n" );
document.write( "f(2003-1930) = 0.2*((2003-1930)/10))<BR>\n" );
document.write( "f(t) = 1.46 secs will be the decrease, so the record speed is <BR>\n" );
document.write( "46.3 - 1.46 = 44.84<BR>\n" );
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document.write( "To find the year when the record will be 44.50<BR>\n" );
document.write( "             46.3 - f(t-1930) = 44.50<BR>\n" );
document.write( "              -f(t-1930) = 44.50 - 46.3<BR>\n" );
document.write( "              -f(t-1930) = -1.8<BR>\n" );
document.write( "              f(t-1939) = 1.8<BR>\n" );
document.write( "              0.2*(t-1930)/10 = 1.8 <BR>\n" );
document.write( "              0.2*t = 18 + 0.2*1930<BR>\n" );
document.write( "                   t = (18 + 386)/0.2<BR>\n" );
document.write( "                   t = 2020 </SPAN>\n" );
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