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: If Karen were a server, then it is late. Karen is driving a car or it is overcast. David is not running. If Karen drives a car, then Karen is a server. David is running if and only if it is overcast.
If Karen drives a car, then it is late can be inferred via the transitivity rule. If it is not overcast, then Karen is driving a car can be inferred via the rewriting rule. If David goes running, then it is overcast can be inferred via the biconditional elimination rule. If it is overcast, then David is running can be inferred via the biconditional elimination rule. It is not overcast can be inferred via the biconditional elimination rule.