document.write( "Question 807732: A boat traveled 210 miles downstream and back. the trip downstream took 10 hours and the trip back took 70 hours. What is the speed of the boat in still water? What is the speed of the current? \n" ); document.write( "
Algebra.Com's Answer #486481 by stanbon(75887)\"\" \"About 
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A boat traveled 210 miles downstream and back. the trip downstream took 10 hours and the trip back took 70 hours. What is the speed of the boat in still water? What is the speed of the current?
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\n" ); document.write( "Rate downstream:: 210/10 = 21 mph
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\n" ); document.write( "Rate upstream::: 210/70 = 3 mph
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\n" ); document.write( "Equations:
\n" ); document.write( "Downstream:: b + c = 21 mph
\n" ); document.write( "Upstream:::: b - c = 3 mph
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\n" ); document.write( "Add and solve for \"b\":
\n" ); document.write( "2b = 24
\n" ); document.write( "b = 12 mph (speed of the boat in still water)
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\n" ); document.write( "Solve for \"c\"::
\n" ); document.write( "b + c = 21
\n" ); document.write( "12 + c = 21
\n" ); document.write( "c = 9 mph (speed of the current)
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H. \n" ); document.write( "
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