Consider the following premises. For all x_13, x_13 is a cashier if and only if x_13 will listen to a song. Susan is a cashier or Sarah is sleeping. Susan is listening to a song or Sarah is not sleeping. Can we infer the following from them? Susan is not listening to a song.
 From the fact that for all x_13, x_13 is a cashier if and only if x_13 will listen to a song we can infer that for all x_13, if x_13 were a cashier, then x_13 is listening to a song. From the fact that for all x_13, if x_13 were a cashier, then x_13 is listening to a song we can infer that if Susan were a cashier, then Susan is listening to a song. From the fact that Susan is listening to a song or Sarah is not sleeping we can infer that if Sarah sleeps, then Susan is listening to a song. Finally, from the fact that if Susan were a cashier, then Susan is listening to a song, that if Sarah sleeps, then Susan is listening to a song, and that Susan is a cashier or Sarah is sleeping we can infer that Susan is listening to a song, which contradicts that Susan is not listening to a song. Therefore, the answer is no.