document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=197828>Question 197828</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A six passenger plan cruises at 180 mph in calm air. If the plane flies 7 miles with the wind in the same amout of times as it flies 5 miles against the wind, then what is the wind speed?\r<BR>\n" );
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document.write( "I am looking for the formula or the way to arrange the equation. I think it might be D=r/t but I'm not sure. I'll solve once I know the formula or how to arrange the equation. <BR>\n" );
document.write( "Thanks so much!! <BR>\n" );
document.write( "Amber </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #148316 by </B><A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><B>jim_thompson5910(35256)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><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=148316\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let w = speed of the wind (in miles per hour)\r<BR>\n" );
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document.write( "Note: if a plane's speed in still air is 180 mph, then the speed with the wind \"w\" is 180+w (since going with the wind speeds up the plane) and the speed against the wind is 180-w (since going against the wind slows the plane down)\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d=rt ALIGN=MIDDLE  ALT=\"d=rt\"   DISABLED_style= \"max-width:90%; height:auto;\" > Start with the distance-rate-time formula\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=7=%28180%2Bw%29t ALIGN=MIDDLE  ALT=\"7=%28180%2Bw%29t\"   DISABLED_style= \"max-width:90%; height:auto;\" > Plug in <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d=7 ALIGN=MIDDLE  ALT=\"d=7\"   DISABLED_style= \"max-width:90%; height:auto;\" > and <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r=180%2Bw ALIGN=MIDDLE  ALT=\"r=180%2Bw\"   DISABLED_style= \"max-width:90%; height:auto;\" > (see above)\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=7%2F%28180%2Bw%29=t ALIGN=MIDDLE  ALT=\"7%2F%28180%2Bw%29=t\"   DISABLED_style= \"max-width:90%; height:auto;\" > Divide both sides by 180+w.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t=7%2F%28180%2Bw%29 ALIGN=MIDDLE  ALT=\"t=7%2F%28180%2Bw%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > Rearrange the equation<BR>\n" );
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document.write( "-------------------------\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d=rt ALIGN=MIDDLE  ALT=\"d=rt\"   DISABLED_style= \"max-width:90%; height:auto;\" > Go back to the distance-rate-time formula\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5=%28180-w%29t ALIGN=MIDDLE  ALT=\"5=%28180-w%29t\"   DISABLED_style= \"max-width:90%; height:auto;\" > Plug in <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d=5 ALIGN=MIDDLE  ALT=\"d=5\"   DISABLED_style= \"max-width:90%; height:auto;\" > and <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r=180-w ALIGN=MIDDLE  ALT=\"r=180-w\"   DISABLED_style= \"max-width:90%; height:auto;\" > (see note above)\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5=%28180-w%29%287%2F%28180%2Bw%29%29 ALIGN=MIDDLE  ALT=\"5=%28180-w%29%287%2F%28180%2Bw%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > Since the times are equal, this means that we can plug in <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t=7%2F%28180%2Bw%29 ALIGN=MIDDLE  ALT=\"t=7%2F%28180%2Bw%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5%28180%2Bw%29=%28180-w%297 ALIGN=MIDDLE  ALT=\"5%28180%2Bw%29=%28180-w%297\"   DISABLED_style= \"max-width:90%; height:auto;\" > Multiply both sides by 180+w.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5%28180%2Bw%29=7%28180-w%29 ALIGN=MIDDLE  ALT=\"5%28180%2Bw%29=7%28180-w%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > Rearrange the terms.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=900%2B5w=1260-7w ALIGN=MIDDLE  ALT=\"900%2B5w=1260-7w\"   DISABLED_style= \"max-width:90%; height:auto;\" > Distribute.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5w=1260-7w-900 ALIGN=MIDDLE  ALT=\"5w=1260-7w-900\"   DISABLED_style= \"max-width:90%; height:auto;\" > Subtract <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=900 ALIGN=MIDDLE  ALT=\"900\"   DISABLED_style= \"max-width:90%; height:auto;\" > from both sides.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5w%2B7w=1260-900 ALIGN=MIDDLE  ALT=\"5w%2B7w=1260-900\"   DISABLED_style= \"max-width:90%; height:auto;\" > Add <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=7w ALIGN=MIDDLE  ALT=\"7w\"   DISABLED_style= \"max-width:90%; height:auto;\" > to both sides.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=12w=1260-900 ALIGN=MIDDLE  ALT=\"12w=1260-900\"   DISABLED_style= \"max-width:90%; height:auto;\" > Combine like terms on the left side.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=12w=360 ALIGN=MIDDLE  ALT=\"12w=360\"   DISABLED_style= \"max-width:90%; height:auto;\" > Combine like terms on the right side.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=w=%28360%29%2F%2812%29 ALIGN=MIDDLE  ALT=\"w=%28360%29%2F%2812%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > Divide both sides by <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=12 ALIGN=MIDDLE  ALT=\"12\"   DISABLED_style= \"max-width:90%; height:auto;\" > to isolate <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=w ALIGN=MIDDLE  ALT=\"w\"   DISABLED_style= \"max-width:90%; height:auto;\" >.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=w=30 ALIGN=MIDDLE  ALT=\"w=30\"   DISABLED_style= \"max-width:90%; height:auto;\" > Reduce.\r<BR>\n" );
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document.write( "Answer:\r<BR>\n" );
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document.write( "So the solution is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=w=30 ALIGN=MIDDLE  ALT=\"w=30\"   DISABLED_style= \"max-width:90%; height:auto;\" > which means that the speed of the wind is 30 mph. </SPAN>\n" );
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