document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=166412>Question 166412</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Can someone please help me with the following problem?\r<BR>\n" );
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document.write( "A plane has a cruising speed of 280 miles per hour and the wind velocity is 40 miles per hour. How far can the plane fly and return in 7 hours?\r<BR>\n" );
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document.write( "So far I have begun to make a chart to help solve the problem, but I am just very confused.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #122648 by </B><A HREF=/tutors/aboutme.mpl?userid=gonzo><B>gonzo(654)</B></A><img src=\"/images/stars/stars-11.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=gonzo><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=122648\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> let D = distance going.<BR>\n" );
document.write( "let D = distance coming back.<BR>\n" );
document.write( "let x = amount of time to get there.<BR>\n" );
document.write( "let y = amount of time to get back.<BR>\n" );
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document.write( "assume the wind velocity is with the plane going and against the plane coming back.<BR>\n" );
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document.write( "rate of speed going is 280 mph of the plane plus 40 mph of the wind = 320 mph.<BR>\n" );
document.write( "rate of speed coming back is 280 mph of the plane minus 40 mph of the wind = 240 mph.<BR>\n" );
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document.write( "rate times time = distance<BR>\n" );
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document.write( "equation for going is:<BR>\n" );
document.write( "320*x = D (equation 1)**********************<BR>\n" );
document.write( "equation for coming back is:<BR>\n" );
document.write( "240*y = D (equation 2)*********************<BR>\n" );
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document.write( "since they both equal D, then they are equal to each other.<BR>\n" );
document.write( "320*x = 240*y<BR>\n" );
document.write( "solve for y<BR>\n" );
document.write( "y = 320*x/240 = (4/3)*x<BR>\n" );
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document.write( "total time going and coming back is 7 hours.<BR>\n" );
document.write( "x + y = 7<BR>\n" );
document.write( "since y = (4/3)*x, equation becomes:<BR>\n" );
document.write( "x + (4/3)*x = 7<BR>\n" );
document.write( "multiply both sides of equation by 3:<BR>\n" );
document.write( "3*x + 4*x = 21<BR>\n" );
document.write( "simplify:<BR>\n" );
document.write( "7*x = 21<BR>\n" );
document.write( "x = 3<BR>\n" );
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document.write( "if x = 3, then y = 4, since x + y = 7<BR>\n" );
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document.write( "plug into original equations 1 and 2.<BR>\n" );
document.write( "equation 1:<BR>\n" );
document.write( "320*3 = D<BR>\n" );
document.write( "D = 960 miles<BR>\n" );
document.write( "equation 2:<BR>\n" );
document.write( "240*4 = D<BR>\n" );
document.write( "D = 960<BR>\n" );
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document.write( "the plane flies 960 miles to get there and 960 miles to get back for a total of 1920 miles.<BR>\n" );
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