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u A The horizontal cross section of a well containing mineral water is a circle of radius 4ft. The cost of pumping the water to an outlet at the top of the well is 2 centavos per ft-lb of work done. If the mineral water weighs 62.5 lb/ft3 and is sold for 2opesos per cu. ft, nd the depth to which the water is to be pumped out to realize a maximum prot. Select one: a. 16ft V b. 20ft ' c. 13ft d. 11ft The correct answer is: 16ft