Consider the following premises. For all y, if y were sad, then y is a cashier. If Patricia were a cashier, then William is not fast. William is fast. If Susan drinks water, then Patricia is sad. Can we infer the following from them? If we can, name the inference rule being used: Susan is not drinking water.
 From the fact that for all y, if y were sad, then y is a cashier we can infer that if Patricia were sad, then Patricia is a cashier via universal instantiation. From the fact that if Patricia were a cashier, then William is not fast, and that William is fast we can infer that Patricia is not a cashier via modus tollens. From the fact that if Susan drinks water, then Patricia is sad, and that if Patricia were sad, then Patricia is a cashier we can infer that if Susan drinks water, then Patricia is a cashier via transitivity. Finally, from the fact that if Susan drinks water, then Patricia is a cashier, and that Patricia is not a cashier we can infer that Susan is not drinking water via modus tollens. Therefore, the answer is yes.