



 
Hi Rachelle, Suppose the speed is x miles per hour and the operating cost is y cents per mile. If the operating cost is a quadratic function of the speed then
Hence when the speed is 10 mph and the cost is 22 cents per mile
Use the second and third rows of data to produce two more equations in a, b and c. Solve these three equations for a, b and c. Write the resulting quadratic equation and substitute x = 60 mph to find the operating cost at that speed. Penny  


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