What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Susan is a scientist. Charles is reading a book. If Charles takes a plane, then Jennifer is writing a letter. If James cooks, then Charles is not reading a book. If Jennifer writes a letter, then Charles is taking a plane. James is cooking if and only if Charles is taking a plane.
James is not cooking. Susan is a scientist and Charles is reading a book. Charles is reading a book and Susan is a scientist. Charles is taking a plane if and only if Jennifer is writing a letter. Jennifer is writing a letter if and only if Charles is taking a plane. If James cooks, then Charles is taking a plane. If Charles takes a plane, then James is cooking.