document.write( "Question 141774This question is from textbook
\n" ); document.write( ": Don uses his small motorboat to go 5 miles upstream to his favorite fishing spot. Against the current, the trip takes 5/6 hour. With the current the trip takes 1/2 hours. How fast can the boat travel in still water. What is the speed of the current?\r
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Algebra.Com's Answer #103275 by ptaylor(2198)\"\" \"About 
You can put this solution on YOUR website!
Distance(d) equals Rate(r) times Time(t) or d=rt; r=d/t and t=d/r
\n" ); document.write( "Let r=speed of the boat in still water
\n" ); document.write( "And let x=rate (speed) of the current
\n" ); document.write( "Going upstream we need to subtract the speed of the current: going downstream we need to add the speed of the current
\n" ); document.write( "Then speed upstream =r-x=5/(5/6)
\n" ); document.write( "5/(5/6): multiply numerator and denominator by 6/5 to get rid of the complex fraction and we get 6
\n" ); document.write( "So, r-x=6--------------------------------------eq1
\n" ); document.write( "And speed downstream=r+x=5/(1/2)=10
\n" ); document.write( "and r+x=10------------------------------------eq2\r
\n" ); document.write( "\n" ); document.write( "add eq1 and eq2
\n" ); document.write( "2r=16 divide both sides by 2
\n" ); document.write( "r=8 mph-----------------------------speed of boat in still water\r
\n" ); document.write( "\n" ); document.write( "substitute r=8 into eq1
\n" ); document.write( "8-x=6 subtract 8 from each side\r
\n" ); document.write( "\n" ); document.write( "8-8-x=6-8 collect like terms\r
\n" ); document.write( "\n" ); document.write( "-x=-2 divide each side by -1
\n" ); document.write( "x=2 mph------------------------------speed of current\r
\n" ); document.write( "\n" ); document.write( "CK
\n" ); document.write( "5 =6*(5/6)
\n" ); document.write( "5=5
\n" ); document.write( "and
\n" ); document.write( "5=10*(1/2)
\n" ); document.write( "5=5\r
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\n" ); document.write( "\n" ); document.write( "Hope this helps---ptaylor\r
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