document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=189422>Question 189422</A>: <I><SPAN STYLE=\"word-break: break-all;\"> These two questions are bogging me down. Please help. \r<BR>\n" );
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document.write( " Upstream, downstream.  Junior’s boat will go 15 miles per hour in still water.  If he can go 12 miles downstream in the same amount of time as it takes to go 9 miles upstream, then what is the speed of the current.\r<BR>\n" );
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document.write( " Big plane.  A six-passenger plane cruises at 180 mph in calm air.  If the plane flies 7 miles with the wind in the same amount of time as it flies 5 miles against the wind, then what is the wind speed?\r<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #142098 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=142098\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Junior’s boat will go 15 miles per hour in still water. If he can go 12 miles downstream in the same amount of time as it takes to go 9 miles upstream, then what is the speed of the current.<BR>\n" );
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document.write( "Let the speed of the current be \"c mph\"<BR>\n" );
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document.write( "Downstream DATA:<BR>\n" );
document.write( "distance = 12 miles ; rate = (15 + c) mph ; time = 12/(15+c) hrs<BR>\n" );
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document.write( "Upstream DATA;<BR>\n" );
document.write( "distance = 9 miles ; rate = (15 - c) mph ; time =  9/(15-c) hrs\r<BR>\n" );
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document.write( "Equation:<BR>\n" );
document.write( "time = time<BR>\n" );
document.write( "12/(15+c) = 9/(15-c)<BR>\n" );
document.write( "4/(15+c) = 3/(15-c)<BR>\n" );
document.write( "Cross-multiply to get:<BR>\n" );
document.write( "4(15-c) = 3(15+c)<BR>\n" );
document.write( "60 - 4c = 45 + 3c<BR>\n" );
document.write( "7c = 15<BR>\n" );
document.write( "c = (15/7) mph -------speed of the current<BR>\n" );
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document.write( "A six-passenger plane cruises at 180 mph in calm air. If the plane flies 7 miles with the wind in the same amount of time as it flies 5 miles against the wind, then what is the wind speed? <BR>\n" );
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document.write( "Let the wind speed be \"w\".<BR>\n" );
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document.write( "With the wind DATA:<BR>\n" );
document.write( "distance = 7 miles : rate = 180+w mph ; time = 7/(180+w) hrs<BR>\n" );
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document.write( "Against the wind DATA:<BR>\n" );
document.write( "distance = 5 miles ; rate = 180-w mph ; time = 5/(180-w) hrs<BR>\n" );
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document.write( "Equation:<BR>\n" );
document.write( "time = time<BR>\n" );
document.write( "7/(180+w) = 5/(180-w)<BR>\n" );
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document.write( "Solve for \"w\".<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.\r<BR>\n" );
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