Consider the following premises. It is overcast or David is making tea. If David makes tea, then Elisabeth is a bartender. If Elisabeth were a bartender, then David is making tea. If it is overcast, then Elisabeth is a bartender. Can we infer the following from them? Elisabeth is not a bartender.
 From the fact that if David makes tea, then Elisabeth is a bartender, and that if Elisabeth were a bartender, then David is making tea we can infer that David is making tea if and only if Elisabeth is a bartender. From the fact that David is making tea if and only if Elisabeth is a bartender we can infer that if David makes tea, then Elisabeth is a bartender. Finally, from the fact that if it is overcast, then Elisabeth is a bartender, that if David makes tea, then Elisabeth is a bartender, and that it is overcast or David is making tea we can infer that Elisabeth is a bartender, which contradicts that Elisabeth is not a bartender. Therefore, the answer is no.