What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? If it is sunny, then Barbara is a mechanic. If Barbara were a mechanic, then it is sunny. If Barbara were a mechanic, then Thomas is fast. Thomas is not fast. If Thomas were fast, then Barbara is a mechanic.
Barbara is not a mechanic. If it is sunny, then Thomas is fast. If Thomas were fast, then it is sunny. It is sunny if and only if Barbara is a mechanic. Barbara is a mechanic if and only if it is sunny. Barbara is a mechanic if and only if Thomas is fast. Thomas is fast if and only if Barbara is a mechanic.