document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1025505>Question 1025505</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A plane flies 500 miles with the wind and 350 miles against the wind in the same length of time. If the speed of the wind is 30 mph, what is the speed of the plane in still air? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #640809 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=640809\">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=+s+ ALIGN=MIDDLE  ALT=\"+s+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = speed of the plane in still air in mi/hr<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+s+%2B+30+ ALIGN=MIDDLE  ALT=\"+s+%2B+30+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = the speed of the plane going with the wind<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+s+-+30+ ALIGN=MIDDLE  ALT=\"+s+-+30+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = the speed of the wind going against the wind<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 for both trips<BR>\n" );
document.write( "----------------------------------<BR>\n" );
document.write( "Equation for going against the wind<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+350+=+%28+s+-+30+%29%2At+ ALIGN=MIDDLE  ALT=\"+350+=+%28+s+-+30+%29%2At+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Equation for going with the wind:<BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+500+=+%28+s+%2B+30+%29%2At+ ALIGN=MIDDLE  ALT=\"+500+=+%28+s+%2B+30+%29%2At+\"   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+=+350+%2F+%28+s+-+30+%29+ ALIGN=MIDDLE  ALT=\"+t+=+350+%2F+%28+s+-+30+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Substitute (1) into (2)<BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+500+=+%28+s+%2B+30+%29%2A%28+350+%2F+%28+s+-+30+%29+%29+ ALIGN=MIDDLE  ALT=\"+500+=+%28+s+%2B+30+%29%2A%28+350+%2F+%28+s+-+30+%29+%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=+500%2A%28+s+-+30+%29+=+350%2A%28+s+%2B+30+%29+ ALIGN=MIDDLE  ALT=\"+500%2A%28+s+-+30+%29+=+350%2A%28+s+%2B+30+%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=+500s+-+15000+=+350s+%2B+10500+ ALIGN=MIDDLE  ALT=\"+500s+-+15000+=+350s+%2B+10500+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+150s+=+25500+ ALIGN=MIDDLE  ALT=\"+150s+=+25500+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+s+=+170+ ALIGN=MIDDLE  ALT=\"+s+=+170+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "The speed of the plane in still air is 170 mi/hr<BR>\n" );
document.write( "check:<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+350+=+%28+s+-+30+%29%2At+ ALIGN=MIDDLE  ALT=\"+350+=+%28+s+-+30+%29%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=+350+=+%28+170+-+30+%29%2At+ ALIGN=MIDDLE  ALT=\"+350+=+%28+170+-+30+%29%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=+350+=+140t+ ALIGN=MIDDLE  ALT=\"+350+=+140t+\"   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+=+2.5+ ALIGN=MIDDLE  ALT=\"+t+=+2.5+\"   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=+500+=+%28+s+%2B+30+%29%2At+ ALIGN=MIDDLE  ALT=\"+500+=+%28+s+%2B+30+%29%2At+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+500+=+%28+170+%2B+30+%29%2At+ ALIGN=MIDDLE  ALT=\"+500+=+%28+170+%2B+30+%29%2At+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+500+=+200t+ ALIGN=MIDDLE  ALT=\"+500+=+200t+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+2.5+ ALIGN=MIDDLE  ALT=\"+t+=+2.5+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "OK </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );