What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: It is not cloudy. Jessica is working. Sarah is a mechanic if and only if it is cloudy.
It is not cloudy and Jessica is working can be inferred via the conjunction rule. Jessica is working and it is not cloudy can be inferred via the conjunction rule. If Sarah were a mechanic, then it is cloudy can be inferred via the biconditional elimination rule. If it is cloudy, then Sarah is a mechanic can be inferred via the biconditional elimination rule. Sarah is not a mechanic can be inferred via the biconditional elimination rule.