document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1121180>Question 1121180</A>: <I><SPAN STYLE=\"word-break: break-all;\"> How would I go about solving this question?\r<BR>\n" );
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document.write( "A construction company pays $12,000 for a truck. The truck depreciates at a constant rate of 20% yearly. How long will it take for the truck to be worth $7200.\r<BR>\n" );
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document.write( "Thanks in advance. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #736943 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><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=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=736943\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 7200=12000(1-.0.20)^n, where n is the number of years.<BR>\n" );
document.write( "0.6=0.80^n<BR>\n" );
document.write( "logs of both sides<BR>\n" );
document.write( "-0.2218=n log 0.80=n*-0.0969<BR>\n" );
document.write( "divide both sides by -0.0969<BR>\n" );
document.write( "=2.29 years<BR>\n" );
document.write( "Rough check<BR>\n" );
document.write( "after 1 year, truck is worth $12000*0.8=$9600<BR>\n" );
document.write( "after 2 years, it is worth $9600*0.8=$7680<BR>\n" );
document.write( "after 3 years, it is worth $7680*0.8=$6144.   The answer above is reasonable. </SPAN>\n" );
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