document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=459117>Question 459117</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A plane flies 900 miles with a tail wind in 3 hours.It takes the same plane 2 hours to fly the 300 miles when flying against the wind. What is the plan's speed 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 #314876 by </B><A HREF=/tutors/aboutme.mpl?userid=oberobic><B>oberobic(2304)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=oberobic><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=314876\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The basic distance equation is:<BR>\n" );
document.write( "d = rt<BR>\n" );
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document.write( "We are told that flying with the tailwind<BR>\n" );
document.write( "900 = r*3<BR>\n" );
document.write( "r = 300<BR>\n" );
document.write( "BUT<BR>\n" );
document.write( "r = speed of the plane + speed of the tailwind<BR>\n" );
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document.write( "We are told flying with the headwind<BR>\n" );
document.write( "300 = r*2<BR>\n" );
document.write( "r = 150<BR>\n" );
document.write( "BUT this time,<BR>\n" );
document.write( "r = speed of the plane - speed of the wind<BR>\n" );
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document.write( "Assuming the wind is constant...which is important.<BR>\n" );
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document.write( "We can define:<BR>\n" );
document.write( "s=speed of the plane<BR>\n" );
document.write( "w=speed of the wind<BR>\n" );
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document.write( "Substitute what we know:<BR>\n" );
document.write( "s+w = 300<BR>\n" );
document.write( "s-w = 150<BR>\n" );
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document.write( "Add the linear equations.<BR>\n" );
document.write( "2s = 450<BR>\n" );
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document.write( "Solve for s<BR>\n" );
document.write( "s = 225<BR>\n" );
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document.write( "Substitute to solve for w<BR>\n" );
document.write( "w = 75<BR>\n" );
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document.write( "Check by substituting these value to see if you get the correct distance.<BR>\n" );
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document.write( "3(225+75) = ??<BR>\n" );
document.write( "3(300) = 900<BR>\n" );
document.write( "Right<BR>\n" );
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document.write( "2(225-75) = ??<BR>\n" );
document.write( "2(150) = 300<BR>\n" );
document.write( "Right<BR>\n" );
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document.write( "Re-read the question to see what answer is required.<BR>\n" );
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document.write( "Answer: The plane's speed in still air is 225 miles/hr.<BR>\n" );
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document.write( "Done. </SPAN>\n" );
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