document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1057766>Question 1057766</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The current in a stream moves at a speed of 4 km/ h. A boat travels 17 km upstream and 17 km downstream in a total time of 10 hr. What is the speed of the boat in still&#8203; water? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #672768 by </B><A HREF=/tutors/aboutme.mpl?userid=jorel555><B>jorel555(1290)</B></A><img src=\"/images/stars/stars-12.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=jorel555><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=672768\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let s be the speed of the boat in still water. Then:<BR>\n" );
document.write( "17/(s+4) + 17/(s-4)=10<BR>\n" );
document.write( "17(s-4)+17(s+4)=10sē-160<BR>\n" );
document.write( "10sē-34s-160=0<BR>\n" );
document.write( "5sē-17s-80=0<BR>\n" );
document.write( "Using the quadratic formula, i.e. <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+ ALIGN=MIDDLE  ALT=\"x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" >, we get two roots: 6.04626276242 and -2.64626276242. Throwing out the negative result, we get the speed of the boat in still water to be 6.04626 kph. &#9786;&#9786;&#9786;&#9786; </SPAN>\n" );
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