Consider the following premises. For all x_11, x_11 is a janitor. For all x_11, x_11 will play a game or x_11 will drive a car. For all x_11, x_11 is not fast. For all x_11, x_11 will play a game if and only if x_11 is fast. Can we infer the following from them? If we can, name the inference rule being used: Barbara is not a janitor.
That contradicts the premises. Therefore the answer is no.