What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all z, z will cook if and only if z is a mechanic. Thomas is fast or Sarah is a mechanic. If Thomas were fast, then Sarah is cooking.
If Sarah sleeps, then Thomas is fast. For all z, if z cooks, then z is a mechanic. For all z, if z were a mechanic, then z is cooking.