Consider the following premises. For all x_6, x_6 is a writer or x_6 is not happy. For all x_6, x_6 is happy. There is at least one x_6 for which x_6 is a taxi driver. Can we infer the following from them? There is at least one x_6 for which x_6 is a writer and x_6 is a taxi driver.
 From the fact that for all x_6, x_6 is a writer or x_6 is not happy we can infer that for all x_6, if x_6 were happy, then x_6 is a writer. From the fact that for all x_6, if x_6 were happy, then x_6 is a writer, and that for all x_6, x_6 is happy we can infer that for all x_6, x_6 is a writer. Finally, from the fact that for all x_6, x_6 is a writer, and that there is at least one x_6 for which x_6 is a taxi driver we can infer that there is at least one x_6 for which x_6 is a writer and x_6 is a taxi driver. Therefore, the answer is yes.