Consider the following premises. For all x_7, x_7 will work or x_7 is a server. For all x_7, if x_7 works, then x_7 is listening to a song. For all x_7, x_7 is a server if and only if x_7 will listen to a song. For all x_7, x_7 is a cashier. Can we infer the following from them? For all x_7, x_7 is a cashier and x_7 will listen to a song.
 From the fact that for all x_7, x_7 is a server if and only if x_7 will listen to a song we can infer that for all x_7, if x_7 were a server, then x_7 is listening to a song. From the fact that for all x_7, if x_7 works, then x_7 is listening to a song, that for all x_7, if x_7 were a server, then x_7 is listening to a song, and that for all x_7, x_7 will work or x_7 is a server we can infer that for all x_7, x_7 will listen to a song. Finally, from the fact that for all x_7, x_7 is a cashier, and that for all x_7, x_7 will listen to a song we can infer that for all x_7, x_7 is a cashier and x_7 will listen to a song. Therefore, the answer is yes.