Ecology—Removing Pollutants: In planning its future operating budget, the city of Rockton...

Ecology—Removing Pollutants: In planning its future operating budget, the city of Rockton hires a consulting firm to determine the cost of removing the pollutants discharged into Lake Watson. They find the cost can be projected by the model

where x represents the percentage of the pollutants removed and C(x) represents the cost in thousands of dollars.

(a) Use the Quotient Rule to differentiate C(x).

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(b) Evaluate C(50) and C′(50) and interpret each.