document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=162653>Question 162653</A>This question is from textbook <A HREF=http://www.amazon.com/exec/obidos/ASIN/0495117935/algebrahomeworkh>beginning and intermediate algebra</A><BR>\n" );
document.write( ": <I><SPAN STYLE=\"word-break: break-all;\"> a plane can fly 400 miles downwind in the same amount of time as it can travel 320 miles upwind.  If the plane can fly at 360 miles per hour in still air. Find the speed of the wind.  I need to revise my exam </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #119906 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=119906\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\">  plane can fly 400 miles downwind in the same amount of time as it can travel 320 miles upwind. If the plane can fly at 360 miles per hour in still air. Find the speed of the wind.<BR>\n" );
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document.write( "Let x = speed of the wind<BR>\n" );
document.write( "then<BR>\n" );
document.write( "(360-x) speed against the wind<BR>\n" );
document.write( "and<BR>\n" );
document.write( "(360+x) speed with the wind<BR>\n" );
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document.write( "It says the times are equal for flying 400 mi and 320 mi. Write a time equation<BR>\n" );
document.write( "time = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=distance%2Fspeed ALIGN=MIDDLE  ALT=\"distance%2Fspeed\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "Time with the wind = time against the wind<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=400%2F%28%28360%2Bx%29%29 ALIGN=MIDDLE  ALT=\"400%2F%28%28360%2Bx%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=320%2F%28%28360-x%29%29 ALIGN=MIDDLE  ALT=\"320%2F%28%28360-x%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Cross multiply<BR>\n" );
document.write( "320(360+x) = 400(360-x)<BR>\n" );
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document.write( "115200 + 320x = 144000 - 400x<BR>\n" );
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document.write( "320x + 400x = 144000 - 114200<BR>\n" );
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document.write( "720x = 28800<BR>\n" );
document.write( "x = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=28800%2F720 ALIGN=MIDDLE  ALT=\"28800%2F720\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "x = 40 mph is the wind<BR>\n" );
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document.write( "Check the solution, find out if the times are equal:<BR>\n" );
document.write( "Using the wind, the speed with 400, speed against 320<BR>\n" );
document.write( "400/400 = 1 hr<BR>\n" );
document.write( "320/320 = 1 hr </SPAN>\n" );
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