document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1203109>Question 1203109</A>: <I><SPAN STYLE=\"word-break: break-all;\"> It took a patrol boat 5 hours to travel 60 km up a river against the current, and 3 hours for the return trip with the current. Find the speed of the boat in still water and the speed of the current. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #838409 by </B><A HREF=/tutors/aboutme.mpl?userid=greenestamps><B>greenestamps(13200)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=greenestamps><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=greenestamps><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=838409\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <br><BR>\n" );
document.write( "Tutor @josgarithmetic loves those magic formulas with lots of variables that you can use to solve a problem like this -- if you like magic formulas and don't care anything about learning HOW to solve the problem.<br><BR>\n" );
document.write( "Tutor Math_tutor2020 provides a valid algebraic solution but using a very slow method.<br><BR>\n" );
document.write( "Tutor @ikleyn uses a quick and easy method to solve the problem.<br><BR>\n" );
document.write( "Choose what fits your taste....<br><BR>\n" );
document.write( "And if formal algebra is not required, this is a common type of problem that can be solved quickly and easily using a bit of logical reasoning and simple arithmetic.<br><BR>\n" );
document.write( "Determine from the given information that the upstream speed is 12 km/hr and the downstream speed is 20 km/hr.<br><BR>\n" );
document.write( "Then use logical reasoning to find the answers.<br><BR>\n" );
document.write( "The 20 km/hr is the boat speed plus the current speed; the 12 km/hr is the boat speed minus the current speed.  Picture that on a number line -- you add the current speed to the boat speed and you get 20 km/hr; you subtract the current speed from the boat speed and you get 12 km/hr.<br><BR>\n" );
document.write( "That means the boat speed is halfway between 20 km/hr and 12 km/hr -- that is, 16 km/hr.  And then the current speed is the difference between 16 km/hr and either 20 km/hr or 12 km/hr -- that is, 4 km/hr.<br><BR>\n" );
document.write( "ANSWERS: boat speed 16 km/hr, current speed 4 km/hr<br><BR>\n" );
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