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: David is playing tennis. If David plays tennis, then Susan is curious. If Elisabeth drives a car, then it is not overcast. It is overcast.
Susan is curious can be inferred via the modus ponens rule. Elisabeth is not driving a car can be inferred via the modus tollens rule. David is playing tennis and it is overcast can be inferred via the conjunction rule. It is overcast and David is playing tennis can be inferred via the conjunction rule.