document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=320481>Question 320481</A>: <I><SPAN STYLE=\"word-break: break-all;\"> With a certain tail wind an airplane reached its destination, 630 miles away, in 1½ hours. Flying back against the same wind, the plane took 15 minutes longer to make the trip. Find the wind speed and the plane's airspeed </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #229509 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=229509\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> With a certain tail wind an airplane reached its destination, 630 miles away, in 1½ hours.<BR>\n" );
document.write( "Flying back against the same wind, the plane took 15 minutes longer to make the trip.<BR>\n" );
document.write( " Find the wind speed and the plane's airspeed<BR>\n" );
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document.write( "Let s = plane's airspeed<BR>\n" );
document.write( "Let w = wind-speed<BR>\n" );
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document.write( "From the given information: tailwind time = 1.5 hrs, against the wind = 1.75 hrs<BR>\n" );
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document.write( "write a distance equation for each trip; dist = time * speed<BR>\n" );
document.write( "1.50(s + w) = 630<BR>\n" );
document.write( "1.75(s - w) = 630<BR>\n" );
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document.write( "We can simplify here; <BR>\n" );
document.write( "divide the 1st equation by 1.5<BR>\n" );
document.write( "divide the 2nd equation by 1.75<BR>\n" );
document.write( "results<BR>\n" );
document.write( "s + w = 420<BR>\n" );
document.write( "s - w = 360<BR>\n" );
document.write( "---------------adding eliminates w, find s<BR>\n" );
document.write( "2s = 780<BR>\n" );
document.write( "s = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=780%2F2 ALIGN=MIDDLE  ALT=\"780%2F2\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "s = 390 mph plane airspeed<BR>\n" );
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document.write( "Find the wind using: s + w = 420<BR>\n" );
document.write( "390 + w = 420<BR>\n" );
document.write( "w = 420 - 390<BR>\n" );
document.write( "w = 30 mph is the wind<BR>\n" );
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document.write( "Check solutions in original return equation<BR>\n" );
document.write( "1.75(390 - 30) = <BR>\n" );
document.write( "1.75(360) = 630; confirms our solutions </SPAN>\n" );
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