document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=115726>Question 115726</A>: <I><SPAN STYLE=\"word-break: break-all;\"> \r<BR>\n" );
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document.write( "A plane flies 720 miles against a steady 30mi/h headwind and then returns to the same point with the wind.  If the entire trip takes 10 hrs, what is the plane's speed in still air?\r<BR>\n" );
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document.write( "720/30 = 10/x<BR>\n" );
document.write( "720x = 30*10<BR>\n" );
document.write( "720x = 300<BR>\n" );
document.write( "720x/720 = 300/720\r<BR>\n" );
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document.write( "Am I on the right track on solving this problem because the answer I come up with is not a whole number? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #84303 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=84303\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> s = the plane's speed in still air<BR>\n" );
document.write( "w = wind speed<BR>\n" );
document.write( "The problem says <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=w+=+30 ALIGN=MIDDLE  ALT=\"w+=+30\"   DISABLED_style= \"max-width:90%; height:auto;\" > mi/hr<BR>\n" );
document.write( "(time going) + (time returning) = total time<BR>\n" );
document.write( "The problems says total time = 10 hrs<BR>\n" );
document.write( "Note that distance/rate = time<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=720+%2F+%28s+-+w%29+%2B+720+%2F+%28s+%2B+w%29+=+10 ALIGN=MIDDLE  ALT=\"720+%2F+%28s+-+w%29+%2B+720+%2F+%28s+%2B+w%29+=+10\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=720+%2F+%28s+-+30%29+%2B+720+%2F+%28s+%2B+30%29+=+10 ALIGN=MIDDLE  ALT=\"720+%2F+%28s+-+30%29+%2B+720+%2F+%28s+%2B+30%29+=+10\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "multiply both sides by <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28s+-+30%29%28s+%2B+30%29 ALIGN=MIDDLE  ALT=\"%28s+-+30%29%28s+%2B+30%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=720%28s+%2B+30%29+%2B+720%28s+-+30%29+=+10%28s+%2B+30%29%28s+-+30%29 ALIGN=MIDDLE  ALT=\"720%28s+%2B+30%29+%2B+720%28s+-+30%29+=+10%28s+%2B+30%29%28s+-+30%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=720s+%2B+21600+%2B+720s+-+21600+=+10%28s%5E2+-+900%29 ALIGN=MIDDLE  ALT=\"720s+%2B+21600+%2B+720s+-+21600+=+10%28s%5E2+-+900%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1440s+=+10s%5E2+-+9000 ALIGN=MIDDLE  ALT=\"1440s+=+10s%5E2+-+9000\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=10s%5E2+-+1440s+-+9000+=+0 ALIGN=MIDDLE  ALT=\"10s%5E2+-+1440s+-+9000+=+0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=s%5E2+-+144s+-+900+=+0 ALIGN=MIDDLE  ALT=\"s%5E2+-+144s+-+900+=+0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "solve using quadratic formula<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=s+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+ ALIGN=MIDDLE  ALT=\"s+=+%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( "a = 1<BR>\n" );
document.write( "b = -144<BR>\n" );
document.write( "c = -900<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=s+=+%28-%28-144%29+%2B-+sqrt%28+%28-144%29%5E2-4%2A1%2A%28-900%29+%29%29%2F%282%2A1%29+ ALIGN=MIDDLE  ALT=\"s+=+%28-%28-144%29+%2B-+sqrt%28+%28-144%29%5E2-4%2A1%2A%28-900%29+%29%29%2F%282%2A1%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=s+=+%28144+%2B-+sqrt%2820736+%2B+3600%29%29+%2F+2 ALIGN=MIDDLE  ALT=\"s+=+%28144+%2B-+sqrt%2820736+%2B+3600%29%29+%2F+2\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=s+=+%28144+%2B-+156%29+%2F+2 ALIGN=MIDDLE  ALT=\"s+=+%28144+%2B-+156%29+%2F+2\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=s+=+150 ALIGN=MIDDLE  ALT=\"s+=+150\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=s+=+-6 ALIGN=MIDDLE  ALT=\"s+=+-6\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "The positive answer is the only one that makes sense<BR>\n" );
document.write( "The plane's speed in still air is 150 mi/hr<BR>\n" );
document.write( "check answer:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=720+%2F+%28s+-+w%29+%2B+720+%2F+%28s+%2B+w%29+=+10 ALIGN=MIDDLE  ALT=\"720+%2F+%28s+-+w%29+%2B+720+%2F+%28s+%2B+w%29+=+10\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=720+%2F+%28150+-+30%29+%2B+720+%2F+%28150+%2B+30%29+=+10 ALIGN=MIDDLE  ALT=\"720+%2F+%28150+-+30%29+%2B+720+%2F+%28150+%2B+30%29+=+10\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=720+%2F+120+%2B+720+%2F+180+=+10 ALIGN=MIDDLE  ALT=\"720+%2F+120+%2B+720+%2F+180+=+10\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=6+%2B+4+=+10 ALIGN=MIDDLE  ALT=\"6+%2B+4+=+10\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "OK </SPAN>\n" );
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