Consider the following premises. For all x_3, x_3 will drink water. There is at least one x_3 for which x_3 is a cashier. For all x_3, if x_3 were a cashier, then x_3 is making tea. Can we infer the following from them? There is at least one x_3 for which x_3 will drink water and x_3 will make tea.
 From the fact that for all x_3, if x_3 were a cashier, then x_3 is making tea, and that there is at least one x_3 for which x_3 is a cashier we can infer that there is at least one x_3 for which x_3 will make tea. Finally, from the fact that for all x_3, x_3 will drink water, and that there is at least one x_3 for which x_3 will make tea we can infer that there is at least one x_3 for which x_3 will drink water and x_3 will make tea. Therefore, the answer is yes.