The temperatures T (in °F) at which water boils at selected pressures p (in pounds per square inch) can be modeled by T = 87.97 + 34.96 In(p) + 7.91V p. Find the rate of change of the temperature (in degrees per pounds per square inch) when the pressure is 80 pounds per square inch. (Round your answer to two decimal places.) degrees per pounds per square inch