What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? If Richard drives a car, then David is reading a book. If Linda writes a letter, then Richard is driving a car. If Mary plays a game, then it is sunny. It is sunny if and only if Linda is writing a letter. David is not reading a book.
Richard is not driving a car. If Linda writes a letter, then David is reading a book. If it is sunny, then Linda is writing a letter. If Linda writes a letter, then it is sunny.