Consider the following premises. For all x_4, x_4 will make tea. For all x_4, if x_4 makes tea, then x_4 is a scientist. There is at least one x_4 for which x_4 is not a scientist. Can we infer the following from them? There is at least one x_4 for which x_4 will climb a mountain.
 From the fact that for all x_4, if x_4 makes tea, then x_4 is a scientist, and that there is at least one x_4 for which x_4 is not a scientist we can infer that there is at least one x_4 for which x_4 will not make tea. From the fact that for all x_4, x_4 will make tea we can infer that for all x_4, x_4 will make tea or x_4 will climb a mountain. Finally, from the fact that for all x_4, x_4 will make tea or x_4 will climb a mountain, and that there is at least one x_4 for which x_4 will not make tea we can infer that there is at least one x_4 for which x_4 will climb a mountain. Therefore, the answer is yes. Notice, however, that the premises were contradictory, so we can infer anything from them.