document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=156637>Question 156637</A>This question is from textbook <A HREF=http://www.amazon.com/exec/obidos/ASIN/013062568X/algebrahomeworkh>Prentice Hall Mathematics Algebra 2</A><BR>\n" );
document.write( ": <I><SPAN STYLE=\"word-break: break-all;\"> 30) Two planes left an airport at noon. One flew east at a certain speed and the other flew west twice the speed. The planes were 2700 mi (miles) apart in 3 h (hours). How fast was each plane flying?\r<BR>\n" );
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document.write( "50) Michael drove to a friend's house at a rate of 40 mi/h (miles per hour). He returned by the same route at a rate of 45 mi/h. The driving time for the round trip was 4 h (hours). What is the distance Michael traveled </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #115440 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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=115440\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Two planes left an airport at noon. <BR>\n" );
document.write( "One flew east at a certain speed ; <BR>\n" );
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document.write( "the other flew west twice the speed.<BR>\n" );
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document.write( "The planes were 2700 mi (miles) apart in 3 h (hours). \r<BR>\n" );
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document.write( "How fast was each plane flying?<BR>\n" );
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document.write( "Combined plane data:<BR>\n" );
document.write( "distance = 2700 miles ; time = 3 hrs ; rate = 2700/3 = 900 mph<BR>\n" );
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document.write( "1st plane rate = x<BR>\n" );
document.write( "2nd plane rate = 2x<BR>\n" );
document.write( "Combined plane rate = 3x mph<BR>\n" );
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document.write( "EQUATION:<BR>\n" );
document.write( "combines rate = combined rate<BR>\n" );
document.write( "3x = 900<BR>\n" );
document.write( "x = 300 mph (1st plane's speed)<BR>\n" );
document.write( "2s = 600 mph (2nd plane's speed)<BR>\n" );
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document.write( "50) Michael drove to a friend's house at a rate of 40 mi/h (miles per hour). <BR>\n" );
document.write( "Outward DATA:<BR>\n" );
document.write( "rate = 40 mph ; distance = x miles ; time = d/r = x/40 hrs<BR>\n" );
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document.write( "He returned by the same route at a rate of 45 mi/h. <BR>\n" );
document.write( "Return DATA:<BR>\n" );
document.write( "rae = 45 mph ; distance = x miles ; time = d/r = x/45 hrs.<BR>\n" );
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document.write( "The driving time for the round trip was 4 h (hours). What is the distance Michael traveled<BR>\n" );
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document.write( "EQUATION:<BR>\n" );
document.write( "time + time = 4 hrs<BR>\n" );
document.write( "x/40 + x/45 = 4<BR>\n" );
document.write( "85x = 4*40*45<BR>\n" );
document.write( "x = 84.71 miles (distance to his friend's house)<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( " </SPAN>\n" );
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