What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? David is drinking water or Richard is a taxi driver. Richard is not a taxi driver or it is cold. David is not drinking water or Joseph is cooking. If it is cold, then it is overcast. Joseph is cooking if and only if it is overcast.
Richard is a taxi driver or Joseph is cooking. If Joseph cooks, then it is overcast. If it is overcast, then Joseph is cooking.