document.write( "Question 520167: This is a Rational Word Problem but i think it still goes under this category. The word problem is: My dog, Pooba, likes to swim in the river. Pooba can swim 6 miles per hour in still water. He can swim 6 miles upstream in the same time it takes to swim 18 miles downstream. What is the speed of the river's current? Please help me. \n" ); document.write( "
Algebra.Com's Answer #345951 by josmiceli(19441)\"\" \"About 
You can put this solution on YOUR website!
Let \"c\" = speed of current in mi/hr
\n" ); document.write( "Let \"s\" = dog's swimming speed in still water in mi/hr
\n" ); document.write( "Let \"t\" = dog's time swimming both upstream
\n" ); document.write( "and downstream in hours
\n" ); document.write( "given:
\n" ); document.write( "\"+s+=+6+\"
\n" ); document.write( "---------
\n" ); document.write( "Swimming upstream:
\n" ); document.write( "(1) \"+6+=+%28+s+-+c+%29%2At+\"
\n" ); document.write( "(1) \"+6+=+%28+6+-+c+%29%2At+\"
\n" ); document.write( "Swimming downstream:
\n" ); document.write( "(2) \"+18+=+%28+s+%2B+c+%29%2At+\"
\n" ); document.write( "(2) \"+18+=+%28+6+%2B+c+%29%2At+\"
\n" ); document.write( "---------------
\n" ); document.write( "(1) \"+6+=+6t+-+c%2At+\"
\n" ); document.write( "(2) \"+18+=+6t+%2B+c%2At+\"
\n" ); document.write( "Add the equations
\n" ); document.write( "\"+24+=+12t+\"
\n" ); document.write( "\"+t+=+2+\"
\n" ); document.write( "and, since
\n" ); document.write( "(1) \"+6+=+6t+-+c%2At+\"
\n" ); document.write( "(1) \"+6+=+6%2A2+-+2c+\"
\n" ); document.write( "(1) \"+2c+=+12+-+6+\"
\n" ); document.write( "(1) \"+2c+=+6+\"
\n" ); document.write( "(1) \"+c+=+3+\"
\n" ); document.write( "The speed of the current is 3 mi/hr
\n" ); document.write( "check answer:
\n" ); document.write( "(2) \"+18+=+%28+6+%2B+c+%29%2At+\"
\n" ); document.write( "(2) \"+18+=+%28+6+%2B+3+%29%2A2+\"
\n" ); document.write( "(2) \"+18+=+9%2A2+\"
\n" ); document.write( "(2) \"+18+=+18+\"
\n" ); document.write( "and
\n" ); document.write( "(1) \"+6+=+6t+-+c%2At+\"
\n" ); document.write( "(1) \"+6+=+6%2A2+-+3%2A2+\"
\n" ); document.write( "(1) \"+6+=+12+-+6+\"
\n" ); document.write( "(1) \"+6+=+6+\"
\n" ); document.write( "OK \n" ); document.write( "
\n" );