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 Joseph reads a book, then Charles is a cashier. For all x_10, if x_10 were a cashier, then x_10 is playing a game. If Charles plays a game, then Joseph is reading a book.
If Charles plays a game, then Charles is a cashier can be inferred via the transitivity rule.