document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=296339>Question 296339</A>: <I><SPAN STYLE=\"word-break: break-all;\"> 4. Translate the problem into a pair of linear equations in two vaiables. Solve the equations using either elimination or substitution. State your answer for the specified variable.<BR>\n" );
document.write( "A plane flying the 3020-mile trip from City A to City B has a 60-mph tailwind. The flight's point of no return is the point at which the flight time required to return to City A is the same as the time required to continue to City B. If the speed of the plane in still air is 430 mph, how far from City A is the point of no return? Round your answer to the nearest mile. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #213584 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=213584\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A plane flying the 3020-mile trip from City A to City B has a 60-mph tailwind.<BR>\n" );
document.write( " The flight's point of no return is the point at which the flight time required<BR>\n" );
document.write( " to return to City A is the same as the time required to continue to City B.<BR>\n" );
document.write( " If the speed of the plane in still air is 430 mph, how far from City A is the <BR>\n" );
document.write( "point of no return?<BR>\n" );
document.write( " Round your answer to the nearest mile.<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Speed with the wind: 430+60 = 490<BR>\n" );
document.write( "Speed against the wind: 430-60 = 370<BR>\n" );
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document.write( "Let x = dist to city A (at point of no return)<BR>\n" );
document.write( "Let y = dist to city B<BR>\n" );
document.write( ";<BR>\n" );
document.write( "Total dist equation<BR>\n" );
document.write( "x + y = 3020<BR>\n" );
document.write( "y = (3020-x); use for substitution<BR>\n" );
document.write( ":<BR>\n" );
document.write( "A travel time equation; <BR>\n" );
document.write( "Time to A = time to B, (the point of no return)<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x%2F370 ALIGN=MIDDLE  ALT=\"x%2F370\"   DISABLED_style= \"max-width:90%; height:auto;\" > = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y%2F490 ALIGN=MIDDLE  ALT=\"y%2F490\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Cross multiply<BR>\n" );
document.write( "490x = 370y<BR>\n" );
document.write( "Simplify divide by 10<BR>\n" );
document.write( "49x = 37y<BR>\n" );
document.write( "Substitute (3020-x) for y<BR>\n" );
document.write( "49x = 37(3020-x)<BR>\n" );
document.write( "49x = 111740 - 37x<BR>\n" );
document.write( "49x + 37x = 111740<BR>\n" );
document.write( "86x = 111740<BR>\n" );
document.write( "x = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=111740%2F86 ALIGN=MIDDLE  ALT=\"111740%2F86\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "x = 1299.3 ~ 1299 mi from A is the point of no return<BR>\n" );
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document.write( ":<BR>\n" );
document.write( "Check solution by finding the times to continue and return, should be equal:<BR>\n" );
document.write( "3020 - 1299 = 1721 mi to B<BR>\n" );
document.write( "1299/370 = 3.5 hr<BR>\n" );
document.write( "1721/490 = 3.5 hr<BR>\n" );
document.write( "(<BR>\n" );
document.write( ":<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );