document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1124828>Question 1124828</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A fisherman rows 12 miles downstream in the same amount of time he rows 4miles upstream, if the current is 6 miles per hour.  Find how long it takes for him to cover 12 miles without any current. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #741301 by </B><A HREF=/tutors/aboutme.mpl?userid=Theo><B>Theo(13342)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Theo><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=Theo><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=741301\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> rate * time = distance.<BR>\n" );
document.write( "fisherman rows 12 miles downstream in the same amount of time that he rows 4 miles upstream.<BR>\n" );
document.write( "let T equal the time.<BR>\n" );
document.write( "the formula going downstream is R * T = 12<BR>\n" );
document.write( "the formula going upstream is R * T = 4<BR>\n" );
document.write( "the current itself is 6 miles per hour.<BR>\n" );
document.write( "going downstream the current is additive and going upstream the current is subtractive.<BR>\n" );
document.write( "the rate going down stream becomes (R + 6) * T = 12<BR>\n" );
document.write( "the rate going up stream becomes (R - 6) * T = 4.<BR>\n" );
document.write( "simplify these two equations to get:<BR>\n" );
document.write( "RT + 6T = 12<BR>\n" );
document.write( "RT - 6T = 4<BR>\n" );
document.write( "subtract the second equation from the first to get:<BR>\n" );
document.write( "12T = 8<BR>\n" );
document.write( "solve for T to get T = 8/12 = 2/3 of an hour.<BR>\n" );
document.write( "going downstream, the equation becomes (R+6) * 2/3 = 12.<BR>\n" );
document.write( "simplify to get 2/3 * R + 2/3 * 6 = 12.<BR>\n" );
document.write( "solve for R to get R = (12 - 2/3 * 6) / (2/3) = 12.<BR>\n" );
document.write( "the speed of the boat without any current is 12 miles per hour.<BR>\n" );
document.write( "going downstream, the formula becomes (12 + 6) * 2/3 = 12 which becomes 18 * 2/3 = 12 which becomes 12 = 12.<BR>\n" );
document.write( "going upstream, the formula becomes (12 - 6) * 2/3 = 4 which becomes 6 * 2/3 = 4 which becomes 4 = 4.<BR>\n" );
document.write( "both equations are true when R = 12, therefore the solution looks good.<BR>\n" );
document.write( "the speed of the boat in still water is 12 miles per hour.<BR>\n" );
document.write( "in still water, the formula of R * T = 12 becomes 12 * T = 12 which results in T = 1.<BR>\n" );
document.write( "in still water, it would take him 1 hour to go 12 miles.<BR>\n" );
document.write( "that's your solution.\r<BR>\n" );
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document.write( " </SPAN>\n" );
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