document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=184155>Question 184155</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A jet, traveling at an average speed of 420 miles per hour in still air, flew 240 miles and back in 1 hour and 10 minutes. What is the average speed of the wind in mph?  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #138221 by </B><A HREF=/tutors/aboutme.mpl?userid=checkley77><B>checkley77(12844)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=checkley77><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=138221\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 240/(420-w)+240/(420+w)=70/60<BR>\n" );
document.write( "[240(420-w)+240(420+w)]/(420+w)(420-w)=70/60<BR>\n" );
document.write( "(100,800-240w+100,800+240w/(176,400-w^2)=70/60<BR>\n" );
document.write( "201,600/(176,400-w^2)=70/60<BR>\n" );
document.write( "60*201,600=70(176,400-70w^2)<BR>\n" );
document.write( "12,096,000=12,348,000-70w^2<BR>\n" );
document.write( "70w^2=-12,096,000+12,348,000=0<BR>\n" );
document.write( "70w^2=252,000<BR>\n" );
document.write( "w^2=252,000/70<BR>\n" );
document.write( "w^2=3600<BR>\n" );
document.write( "w=sqrt3600<BR>\n" );
document.write( "w=60 mph. for the wind.<BR>\n" );
document.write( "Proof:<BR>\n" );
document.write( "240/(420-60)+240/(420+60)=70/60<BR>\n" );
document.write( "240/360+240/480=70/60<BR>\n" );
document.write( "2/3+1/2=7/6<BR>\n" );
document.write( "7/6=7/6\r<BR>\n" );
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