Consider the following premises. If Robert plays a game, then Robert is a sailor. If it is late, then it is cloudy. If it is cloudy, then Robert is playing a game. If Robert were a sailor, then it is late. Can we infer the following from them? If is not true that it is cloudy if and only if Robert is a sailor.
 From the fact that if Robert were a sailor, then it is late, and that if it is late, then it is cloudy we can infer that if Robert were a sailor, then it is cloudy. From the fact that if it is cloudy, then Robert is playing a game, and that if Robert plays a game, then Robert is a sailor we can infer that if it is cloudy, then Robert is a sailor. Finally, from the fact that if it is cloudy, then Robert is a sailor, and that if Robert were a sailor, then it is cloudy we can infer that it is cloudy if and only if Robert is a sailor, which contradicts that If is not true that it is cloudy if and only if Robert is a sailor. Therefore, the answer is no.