document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=118448>Question 118448</A>This question is from textbook <A HREF=http://www.amazon.com/exec/obidos/ASIN/0395977223/algebrahomeworkh>structure and method book 1</A><BR>\n" );
document.write( ": <I><SPAN STYLE=\"word-break: break-all;\"> I AM WORKING ON THE aMERICAN SCHOOL CIRICULUM AND I AM DOING A HOME TEST.  I HAVE THE FOLLOWING WORD PROBLEM AND I CAN'T UNDERSTAND HOW TO GET THE TWO ANSWERS ASKED FOR.  \r<BR>\n" );
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document.write( "A SAILBOAT TRAVELS 20 MILES DOWNSTREAM IN 3 HOURS.IT RETURNS IN 4 HOURS.FIND THE SPEED OF THE SAILBOAT IN STILL WATERAND THE RATE OF THE CURRENT.\r<BR>\n" );
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document.write( "I CAN FIGURE OUT THAT THE RATE OF THE BOAT GOING DOWN STREAM WOULD TRAVEL 6.23 MPH AND COMMING BACK IT WOULD TRAVEL 5 MPH.  I CAN'T FIGURE OUT HOW THAT WILL HELP ME. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #86568 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=86568\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A SAILBOAT TRAVELS 20 MILES DOWNSTREAM IN 3 HOURS.IT RETURNS IN 4 HOURS. FIND THE SPEED OF THE SAILBOAT IN STILL WATER AND THE RATE OF THE CURRENT.<BR>\n" );
document.write( "I CAN FIGURE OUT THAT THE RATE OF THE BOAT GOING DOWN STREAM WOULD TRAVEL 6.23 MPH AND COMING BACK IT WOULD TRAVEL 5 MPH.<BR>\n" );
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document.write( "One way is to use two unknowns and use the elimination method<BR>\n" );
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document.write( "Let x = speed of the boat in still water<BR>\n" );
document.write( "Let y = speed of the current<BR>\n" );
document.write( "then:<BR>\n" );
document.write( "(x+y) = speed downstream<BR>\n" );
document.write( "(x-y) = speed upstream<BR>\n" );
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document.write( "Write two distance equations: Distance = speed * time<BR>\n" );
document.write( "Down stream: 3(x+y) = 20<BR>\n" );
document.write( "Upstream:    4(x-y) = 20<BR>\n" );
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document.write( "3x + 3y = 20<BR>\n" );
document.write( "4x - 4y = 20<BR>\n" );
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document.write( "Multiply the 1st equation by 4 and the 2nd equation by 3<BR>\n" );
document.write( "12x + 12y = 80<BR>\n" );
document.write( "12x - 12y = 60<BR>\n" );
document.write( "---------------adding eliminates y, find x<BR>\n" );
document.write( "24x + 0y = 140<BR>\n" );
document.write( "x = 140/24<BR>\n" );
document.write( "x = 5.83 mph speed of the boat in still water<BR>\n" );
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document.write( "Find y<BR>\n" );
document.write( "3(5.833) + 3y = 20<BR>\n" );
document.write( "17.5 + 3y = 20<BR>\n" );
document.write( "3y = 20 - 17.5<BR>\n" );
document.write( "3y = 2.5<BR>\n" );
document.write( "y = 2.5/3<BR>\n" );
document.write( "y = .833 mph is the speed of the current<BR>\n" );
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document.write( "Check solutions in the 2nd equation<BR>\n" );
document.write( "4(5.833) - 4(.833) =<BR>\n" );
document.write( " 23.33 - 3.33 = 20 confirms our solution<BR>\n" );
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