document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=327192>Question 327192</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Which set of equations would be used to solve this word problem?\r<BR>\n" );
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document.write( "An airplane flew 4.5 hours with a 45 mph head wind. The return trip with a tail wind of the same speed took 2.5 hours. Find the speed of the plane in still air.\r<BR>\n" );
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document.write( "a.] None of these systems can be used to solve this problem.\r<BR>\n" );
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document.write( "b.] d = 7(r + 45)\r<BR>\n" );
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document.write( "c.] d = 4.5(r + 45) and d = 2.5(r &#8722; 45)\r<BR>\n" );
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document.write( "d.] d = 4.5(r &#8722; 45) and d = 2.5(r + 45) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #234382 by </B><A HREF=/tutors/aboutme.mpl?userid=galactus><B>galactus(183)</B></A><img src=\"/images/stars/stars-09.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=galactus><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=galactus><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=234382\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A head wind means it is flying into the wind and a tail wind means it is flying with the wind.\r<BR>\n" );
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document.write( "The rate with the wind(tailwind) is r+45\r<BR>\n" );
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document.write( "The rate against the wind(headwind) is r-45\r<BR>\n" );
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document.write( "Since d=rt, we have 4.5(r-45)=2.5(r+45)\r<BR>\n" );
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document.write( "4.5r-202.5=2.5r+112.5\r<BR>\n" );
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document.write( "2r=315\r<BR>\n" );
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document.write( "r=157.5 mph </SPAN>\n" );
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