Power/Energy Problem (6.3)

        Determine the resistance of a 1 watt light bulb designed to be used with three (3)
 volts, the voltage produced by two batteries in series.The town of Lewisburg, PA (population 6000) is situated on the banks of the Susquehanna River (elevation 440 feet above sea level).  The town is relatively isolated, and wants to make some provision should the electrical supply to the town be interrupted. Two water storage tanks (1 million gallons and .25 million gallons) are located on a hill overlooking the river (elevation 560 feet).  Each tank is 40 ft high.  Estimate how long the residents of Lewisburg will be supplied with energy if the energy from the water in the tanks can be used to drive a generator that will power the entire town. Make whatever assumptions seem appropriate using whatever assumptions and justifications seem reasonable.  Your answer will be within an order of magnitude at best.