What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? If it is late, then Richard is a mechanic. Barbara is playing a game or it is late. Richard is a mechanic if and only if Barbara is playing a game. If Richard were a mechanic, then Barbara is playing a game.
If it is late, then Barbara is playing a game. If Richard were a mechanic, then Barbara is playing a game. If Barbara plays a game, then Richard is a mechanic.