document.write( "Question 1072659: 2. Assume that the cost of fuel for a ship is proportional to the cube of velocity of the ship. When the velocity is 10 km/h the cost of fuel is $80 per hour, and other expenses for the ship are $480 per hour.
\n" ); document.write( "What velocity of the ship minimizes the total expenses if the ship sails 20km?
\n" ); document.write( "In this case what are the total expenses per hour?
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Algebra.Com's Answer #687508 by ankor@dixie-net.com(22740)\"\" \"About 
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2. Assume that the cost of fuel for a ship is proportional to the cube of velocity of the ship.
\n" ); document.write( " When the velocity is 10 km/h the cost of fuel is $80 per hour, and other expenses for the ship are $480 per hour.
\n" ); document.write( "What velocity of the ship minimizes the total expenses if the ship sails 20km?
\n" ); document.write( "In this case what are the total expenses per hour?
\n" ); document.write( ":
\n" ); document.write( "Fuel cost equation
\n" ); document.write( "v^3*k = cost/hr
\n" ); document.write( "Using the given values
\n" ); document.write( "10^3*k = 80
\n" ); document.write( "1000k = 80
\n" ); document.write( "k = \"80%2F1000\"
\n" ); document.write( "k = .08
\n" ); document.write( "The hourly fuel cost expression = .08v^3
\n" ); document.write( ":
\n" ); document.write( "Cost equation for a 20 km
\n" ); document.write( "C(v) = \"20%2Fv\"(.08v^3 + 480)
\n" ); document.write( "graphically
\n" ); document.write( "\"+graph%28+300%2C+200%2C+-6%2C+30%2C+-200%2C+2000%2C+%2820%2Fx%29%28.08x%5E3%2B480%29%29+\"
\n" ); document.write( "Minimum cost at a velocity of 14.4 km/hr
\n" ); document.write( ":
\n" ); document.write( "\"In this case what are the total expenses per hour?\"
\n" ); document.write( ".08(14.4^3) = $238.87 per hr
\n" ); document.write( ":
\n" ); document.write( "Cost for a 20 km trip
\n" ); document.write( "C(v) = \"20%2F14.4\"(.08*14.4^3 + 480)
\n" ); document.write( "C(v) = $998.44
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