document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1154641>Question 1154641</A>: <I><SPAN STYLE=\"word-break: break-all;\"> An empty freight train traveled 60 miles from an auto assembly plant to an oil refinery. There, its tank cars were filled with petroleum products, and it returned on the same route to the plant. The total travel time for the train was <BR>\n" );
document.write( "3 1/2 hours.  If the train traveled 10 mph slower with the tank cars full, how fast did the train travel in each direction? thanks </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #777114 by </B><A HREF=/tutors/aboutme.mpl?userid=josmiceli><B>josmiceli(19441)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=josmiceli><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=josmiceli><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=777114\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+r+ ALIGN=MIDDLE  ALT=\"+r+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = rate with tank empty<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+r+-+10+ ALIGN=MIDDLE  ALT=\"+r+-+10+\"   DISABLED_style= \"max-width:90%; height:auto;\" > rate with tank full<BR>\n" );
document.write( "Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+ ALIGN=MIDDLE  ALT=\"+t+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = time in hrs with tank empty<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+3.5+-+t+ ALIGN=MIDDLE  ALT=\"+3.5+-+t+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = time with tank full<BR>\n" );
document.write( "---------------------------------------------<BR>\n" );
document.write( "With tank empty:<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+60+=+r%2At+ ALIGN=MIDDLE  ALT=\"+60+=+r%2At+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "With tank full:<BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+60+=+%28+r+-+10+%29%2A%28+3.5+-+t+%29+ ALIGN=MIDDLE  ALT=\"+60+=+%28+r+-+10+%29%2A%28+3.5+-+t+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "----------------------------------------<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+60%2Fr+ ALIGN=MIDDLE  ALT=\"+t+=+60%2Fr+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+60+=+%28+r+-+10+%29%2A%28+3.5+-+60%2Fr+%29+ ALIGN=MIDDLE  ALT=\"+60+=+%28+r+-+10+%29%2A%28+3.5+-+60%2Fr+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+60+=+3.5r+-+35+-+60+%2B+600%2Fr+ ALIGN=MIDDLE  ALT=\"+60+=+3.5r+-+35+-+60+%2B+600%2Fr+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+155+=+3.5r+%2B+600%2Fr+ ALIGN=MIDDLE  ALT=\"+155+=+3.5r+%2B+600%2Fr+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+155r+=+3.5r%5E2+%2B+600+ ALIGN=MIDDLE  ALT=\"+155r+=+3.5r%5E2+%2B+600+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+3.5r%5E3+-+155r+%2B+600+=+0+ ALIGN=MIDDLE  ALT=\"+3.5r%5E3+-+155r+%2B+600+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+35r%5E2+-+1550r+%2B+6000+=+0+ ALIGN=MIDDLE  ALT=\"+35r%5E2+-+1550r+%2B+6000+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+7r%5E2+-+310r+%2B+1200+=+0+ ALIGN=MIDDLE  ALT=\"+7r%5E2+-+310r+%2B+1200+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+r+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+ ALIGN=MIDDLE  ALT=\"+r+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+a+=+7+ ALIGN=MIDDLE  ALT=\"+a+=+7+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+b+=+-310+ ALIGN=MIDDLE  ALT=\"+b+=+-310+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+c+=+1200+ ALIGN=MIDDLE  ALT=\"+c+=+1200+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+r+=+%28-%28-310%29+%2B-+sqrt%28+%28-310%29%5E2-4%2A7%2A1200+%29%29%2F%282%2A7%29+ ALIGN=MIDDLE  ALT=\"+r+=+%28-%28-310%29+%2B-+sqrt%28+%28-310%29%5E2-4%2A7%2A1200+%29%29%2F%282%2A7%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+r+=+%28310+%2B-+sqrt%28+96100+-+33600+%29%29%2F14+ ALIGN=MIDDLE  ALT=\"+r+=+%28310+%2B-+sqrt%28+96100+-+33600+%29%29%2F14+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+r+=+%28310+%2B-+sqrt%28+62500+%29%29%2F14+ ALIGN=MIDDLE  ALT=\"+r+=+%28310+%2B-+sqrt%28+62500+%29%29%2F14+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+r+=+%28+310+-+250+%29+%2F+14+ ALIGN=MIDDLE  ALT=\"+r+=+%28+310+-+250+%29+%2F+14+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+r+=+60%2F14+ ALIGN=MIDDLE  ALT=\"+r+=+60%2F14+\"   DISABLED_style= \"max-width:90%; height:auto;\" > too slow<BR>\n" );
document.write( "---------------------------<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+r+=+%28+310+%2B+250+%29+%2F+14+ ALIGN=MIDDLE  ALT=\"+r+=+%28+310+%2B+250+%29+%2F+14+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+r+=+560%2F14+ ALIGN=MIDDLE  ALT=\"+r+=+560%2F14+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+r+=+40+ ALIGN=MIDDLE  ALT=\"+r+=+40+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "The train's speed with tank empty was 40 mi/hr<BR>\n" );
document.write( "The train's speed with tank full was 30 mi/hr<BR>\n" );
document.write( "--------------------------------------------------<BR>\n" );
document.write( "check:<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+60+=+r%2At+ ALIGN=MIDDLE  ALT=\"+60+=+r%2At+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+60+=+40%2At+ ALIGN=MIDDLE  ALT=\"+60+=+40%2At+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+1.5+ ALIGN=MIDDLE  ALT=\"+t+=+1.5+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "and<BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+60+=+%28+r+-+10+%29%2A%28+3.5+-+t+%29+ ALIGN=MIDDLE  ALT=\"+60+=+%28+r+-+10+%29%2A%28+3.5+-+t+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+60+=+%28+40+-+10+%29%2A%28+3.5+-+1.5+%29+ ALIGN=MIDDLE  ALT=\"+60+=+%28+40+-+10+%29%2A%28+3.5+-+1.5+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+60+=+30%2A2+ ALIGN=MIDDLE  ALT=\"+60+=+30%2A2+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+60+=+60+ ALIGN=MIDDLE  ALT=\"+60+=+60+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "OK\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );