document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=459572>Question 459572</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Please help me solve this problem. A land investment company purchase a parcel of land for $7200. After having sold all but 20 acres at a profit of $30 per acre over original cost per acre, the company regained the entire cost of the parcel. How many acres were sold? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #315343 by </B><A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><B>ankor@dixie-net.com(22740)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><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=ankor@dixie-net.com><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=315343\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A land investment company purchase a parcel of land for $7200.<BR>\n" );
document.write( " After having sold all but 20 acres at a profit of $30 per acre over original<BR>\n" );
document.write( " cost per acre, the company regained the entire cost of the parcel.<BR>\n" );
document.write( " How many acres were sold?<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Let x = no. of acres sold<BR>\n" );
document.write( "then<BR>\n" );
document.write( "(x+20) = total no. of acres in the parcel<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Selling price - cost price = $30<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=7200%2Fx ALIGN=MIDDLE  ALT=\"7200%2Fx\"   DISABLED_style= \"max-width:90%; height:auto;\" > - <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=7200%2F%28%28x%2B20%29%29 ALIGN=MIDDLE  ALT=\"7200%2F%28%28x%2B20%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 30<BR>\n" );
document.write( ":<BR>\n" );
document.write( "multiply by x(x+20), results:<BR>\n" );
document.write( "7200(x+20) - 7200x = 30x(x+20)<BR>\n" );
document.write( "7200x + 144000 - 7200x = 30x^2 + 600x<BR>\n" );
document.write( "A quadratic equation<BR>\n" );
document.write( "30x^2 + 600x - 144000 = 0<BR>\n" );
document.write( "Simplify, divide by 30<BR>\n" );
document.write( "x^2 + 20x - 4800 = 0<BR>\n" );
document.write( "Factor this to<BR>\n" );
document.write( "(x+80)(x-60) = 0<BR>\n" );
document.write( "positive solution<BR>\n" );
document.write( "x = 60 acres sold<BR>\n" );
document.write( ":<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Check this (total acres 20 more, 80)<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=7200%2F60 ALIGN=MIDDLE  ALT=\"7200%2F60\"   DISABLED_style= \"max-width:90%; height:auto;\" > - <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=7200%2F80 ALIGN=MIDDLE  ALT=\"7200%2F80\"   DISABLED_style= \"max-width:90%; height:auto;\" > = <BR>\n" );
document.write( "$120 - $90 = $30; confirms our solution of x=60<BR>\n" );
document.write( " </SPAN>\n" );
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