What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: Elisabeth is driving a car if and only if it is cloudy. If Elisabeth drives a car, then it is late. If it is late, then Elisabeth is driving a car.
Elisabeth is driving a car if and only if it is late can be inferred via the biconditional introduction rule. It is late if and only if Elisabeth is driving a car can be inferred via the biconditional introduction rule. If Elisabeth drives a car, then it is cloudy can be inferred via the biconditional elimination rule. If it is cloudy, then Elisabeth is driving a car can be inferred via the biconditional elimination rule.