document.write( "Question 767511: A motorboat travels 756 mi in 9 hours going upstream and 684 mi in 6 hours going downstream. What is the rate of the boat in still water and what is the rate of the current? \n" ); document.write( "

Algebra.Com's Answer #467645 by stanbon(75887) $\"\"$ $\"About$

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A motorboat travels 756 mi in 9 hours going upstream and 684 mi in 6 hours going downstream. What is the rate of the boat in still water and what is the rate of the current?
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\n" ); document.write( "Upstream DATA:
\n" ); document.write( "distance = 756 miles ; time = 9 hrs ; rate = 756/9 = 84 mph
\n" ); document.write( "------
\n" ); document.write( "Downstream DATA:
\n" ); document.write( "distance = 684 miles ; time = 6 hrs ; rate = 684/6 = 114 mph
\n" ); document.write( "-------
\n" ); document.write( "Equations:
\n" ); document.write( "b - c = 84
\n" ); document.write( "b + c = 114
\n" ); document.write( "------
\n" ); document.write( "2b = 198
\n" ); document.write( "b = 99 mph (speed of the boat in still water)
\n" ); document.write( "------
\n" ); document.write( "Solve for \"c\":
\n" ); document.write( "b +c = 114
\n" ); document.write( "99 + c = 114
\n" ); document.write( "c = 15 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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