document.write( "Question 131478This question is from textbook
\n" ); document.write( ": It takes a motorboat 4 hours to travel 56 miles down a river, and 3 hours longer to make the return trip. Find the speed of the river current. \n" ); document.write( "
Algebra.Com's Answer #95964 by stanbon(75887)\"\" \"About 
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It takes a motorboat 4 hours to travel 56 miles down a river, and 3 hours longer to make the return trip. Find the speed of the river current.
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\n" ); document.write( "Downstream DATA:
\n" ); document.write( "Time = 4 hr ; distance = 56 miles ; rate = d/t = 56/4 = 14 mph
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\n" ); document.write( "Upstream DATA:
\n" ); document.write( "Time = 7 hr ; distance = 56 miles ; rate = d/t = 56/7 = 8 mph
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\n" ); document.write( "Let boat speed be \"b\"; Let water speed be \"w\"
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\n" ); document.write( "EQUATIONS:
\n" ); document.write( "b+w = 14
\n" ); document.write( "b-w = 8
\n" ); document.write( "Add to get:
\n" ); document.write( "2b = 22
\n" ); document.write( "b = 11 mph (boat speed in still water)
\n" ); document.write( "Substitute to get water speed:
\n" ); document.write( "11+w = 14
\n" ); document.write( "w = 3 mph (water speed)
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H. \n" ); document.write( "
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