document.write( "Question 938614: Billy took a boat to Cuba. It took him 6 hours to travel 80 km against the current and on the way back it took 2 hours. What is the average speed of the boat in still water and what is the speed of the current? \n" ); document.write( "
Algebra.Com's Answer #571838 by stanbon(75887)\"\" \"About 
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Billy took a boat to Cuba. It took him 6 hours to travel 80 km against the current and on the way back it took 2 hours. What is the average speed of the boat in still water and what is the speed of the current?
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\n" ); document.write( "Against current DATA:
\n" ); document.write( "time = 6 hrs ; dist = 80 km ; rate = 80/6 = 40/3 km/hr
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\n" ); document.write( "With current DATA:
\n" ); document.write( "time = 2 hrs ; dist = 80 km ; rate = 80/2 = 40 km/hr
\n" ); document.write( "-------
\n" ); document.write( "Equations:
\n" ); document.write( "Against:: b - c = 40/3 km/hr
\n" ); document.write( "With::::: b + c = 40 km/hr
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\n" ); document.write( "Add to solve for \"b\"::
\n" ); document.write( "2b = 160/3
\n" ); document.write( "b = 80/3 km/hr (speed of the boat in still water)
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\n" ); document.write( "Subtract to solve for \"c\"::
\n" ); document.write( "2c = (2/3)40
\n" ); document.write( "c = (1/3)40
\n" ); document.write( "c = 13 1/3 km/hr (speed of the current)
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\n" ); document.write( "cheers,
\n" ); document.write( "Stan H.
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