Consider the following premises. If John were an electrician, then Robert is driving a car. If Jennifer were a cashier, then John is an electrician. Robert is driving a car or Jennifer is a cashier. John is an electrician if and only if Robert is driving a car. Can we infer the following from them? John is an electrician.
 From the fact that John is an electrician if and only if Robert is driving a car we can infer that if Robert drives a car, then John is an electrician. From the fact that if John were an electrician, then Robert is driving a car, and that if Robert drives a car, then John is an electrician we can infer that John is an electrician if and only if Robert is driving a car. From the fact that John is an electrician if and only if Robert is driving a car we can infer that if Robert drives a car, then John is an electrician. Finally, from the fact that if Robert drives a car, then John is an electrician, that if Jennifer were a cashier, then John is an electrician, and that Robert is driving a car or Jennifer is a cashier we can infer that John is an electrician. Therefore, the answer is yes.