SOLUTION: The amount of oil use by a ship traveling at a uniform speed varies jointly with the distance and the square of the speed. If the ship uses 450 barrels of oil traveling 500 miles a

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Question 970471: The amount of oil use by a ship traveling at a uniform speed varies jointly with the distance and the square of the speed. If the ship uses 450 barrels of oil traveling 500 miles at 40 miles per hour, determine how many barrels of oil are used when the ship travels 400 miles at 20 miles per hour
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
oil= k(d)(s^2)
450=k * 500 * 40^2=500* 1600
(450)/(500*1600) =0.0005625=k
oil (second part)= 0.0005625*400*20^2
This is 0.0005625 * 400^2=
90 BARRELS
CHECK
THE SPEED IS HALVED AND THE DISTANCE IS LESSENED BY 20%
450 barrels *(1/4) (halving the speed squared)=112.5
20% less is 22.5
subtract and get 90.