document.write( "Question 701751: For the following problem, clearly define the variable(s) and write an equation that could be used to solve the problem. What are the units of the answer.\r
\n" ); document.write( "\n" ); document.write( "Two tugboats that have the same speed in still water travel in opposite directions in a river with a constant current of 5 miles per hour. The tugboats departed at the same time from a refueling station; and after a period of time, one has traveled 30 miles downstream and the other has traveled 6 miles upstream. Determine the rate of each boat in still water. \n" ); document.write( "

Algebra.Com's Answer #432578 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let $\"+s+\"$ = their speed in still water in mi/hr
\n" ); document.write( " $\"+s+%2B+5+\"$ = tugboat's speed going with the current in mi/hr
\n" ); document.write( " $\"+s+-+5+\"$ = tugboat's speed going against the current in mi/hr
\n" ); document.write( "--------------
\n" ); document.write( "Equation for tugboat going upstream:
\n" ); document.write( "(1) $\"+6+=+%28+s+-+5+%29%2At+\"$
\n" ); document.write( "Equation for tugboat going downstream:
\n" ); document.write( "(2) $\"+30+=+%28+s+%2B+5+%29%2At+\"$
\n" ); document.write( "--------------------
\n" ); document.write( "(1) $\"+6+=+s%2At+-+5t+\"$
\n" ); document.write( "(2) $\"+30+=+s%2At+%2B+5t+\"$
\n" ); document.write( "Subtract (1) from (2)
\n" ); document.write( "(2) $\"+30+=+s%2At+%2B+5t+\"$
\n" ); document.write( "(1) $\"+-6+=+-s%2At+%2B+5t+\"$
\n" ); document.write( " $\"+24+=+10t+\"$
\n" ); document.write( " $\"+t+=+2.4+\"$ hrs
\n" ); document.write( "and
\n" ); document.write( "(1) $\"+6+=+%28+s+-+5+%29%2A2.4+\"$
\n" ); document.write( "(1) $\"+6+=+2.4s+-+12+\"$
\n" ); document.write( "(1) $\"+2.4s+=+18+\"$
\n" ); document.write( "(1) $\"+s+=+7.5+\"$
\n" ); document.write( "Their speeds in still water is 7.5 mi / hr
\n" ); document.write( "check:
\n" ); document.write( "(2) $\"+30+=+%28+s+%2B+5+%29%2At+\"$
\n" ); document.write( "(2) $\"+30+=+%28+7.5+%2B+5+%29%2A2.4+\"$
\n" ); document.write( "(2) $\"+30+=+12.5%2A2.4+\"$
\n" ); document.write( "(2) $\"+30+=+30+\"$
\n" ); document.write( "OK
\n" ); document.write( "(1) $\"+6+=+%28+s+-+5+%29%2At+\"$
\n" ); document.write( "(1) $\"+6+=+%28+7.5+-+5+%29%2A2.4+\"$
\n" ); document.write( "(1) $\"+6+=+2.5%2A2.4+\"$
\n" ); document.write( "(1) $\"+6+=+6+\"$
\n" ); document.write( "OK
\n" ); document.write( " \n" ); document.write( "

\n" );