Consider the following premises. If Karen drives a car, then Jessica is a scientist. If Jessica were a scientist, then Barbara is a nurse. If Charles cooks, then Karen is driving a car. If Barbara were a nurse, then Charles is fast. Can we infer the following from them? If Charles cooks, then Charles is fast.
 From the fact that if Karen drives a car, then Jessica is a scientist, and that if Jessica were a scientist, then Barbara is a nurse we can infer that if Karen drives a car, then Barbara is a nurse. From the fact that if Karen drives a car, then Barbara is a nurse, and that if Barbara were a nurse, then Charles is fast we can infer that if Karen drives a car, then Charles is fast. Finally, from the fact that if Charles cooks, then Karen is driving a car, and that if Karen drives a car, then Charles is fast we can infer that if Charles cooks, then Charles is fast. Therefore, the answer is yes.