Chemical analysis of an oil reservoir brine yielded the following results: 50,000 ppm Na+, 60,000 ppm 1, 15,000 ppm Mg2+, 12,000 ppm So2+, 8,000 ppm HCO3, Calculate: (1) the equivalent salinity in ppm sodium chloride, and (2) the resisitivity of the brine at 100, 175, and 250F; discuss the effect of temperature on the resistivity of water