Consider the following premises. For all x_10, if x_10 drives a car, then x_10 is fast. Barbara is not fast. Barbara is driving a car if and only if Jennifer is sad. Can we infer the following from them? Jennifer is not sad.
 From the fact that for all x_10, if x_10 drives a car, then x_10 is fast we can infer that if Barbara drives a car, then Barbara is fast. From the fact that if Barbara drives a car, then Barbara is fast, and that Barbara is not fast we can infer that Barbara is not driving a car. Finally, from the fact that Barbara is driving a car if and only if Jennifer is sad, and that Barbara is not driving a car we can infer that Jennifer is not sad. Therefore, the answer is yes.