Consider the following premises. For all x_8, x_8 will sleep or x_8 is an office clerk. There is at least one x_8 for which if x_8 takes a plane, then x_8 is not playing squash. For all x_8, if x_8 were an office clerk, then x_8 is not writing a letter. For all x_8, x_8 will write a letter. For all x_8, x_8 will not sleep or x_8 will play squash. Can we infer the following from them? If we can, name the inference rule being used: For all x_8, x_8 will not sleep or x_8 will play squash.
That is one of the premises. Therefore, the answer is yes.