Consider the following premises. For all y_2, if y_2 makes tea, then y_2 is sleeping. For all y_2, y_2 is a cashier or y_2 will not sleep. There is at least one y_2 for which y_2 is a cashier if and only if y_2 will climb a mountain. Can we infer the following from them? There is at least one y_2 for which if y_2 makes tea, then y_2 is climbing a mountain.
 From the fact that there is at least one y_2 for which y_2 is a cashier if and only if y_2 will climb a mountain we can infer that there is at least one y_2 for which if y_2 were a cashier, then y_2 is climbing a mountain. From the fact that for all y_2, y_2 is a cashier or y_2 will not sleep we can infer that for all y_2, if y_2 sleeps, then y_2 is a cashier. From the fact that for all y_2, if y_2 makes tea, then y_2 is sleeping, and that for all y_2, if y_2 sleeps, then y_2 is a cashier we can infer that for all y_2, if y_2 makes tea, then y_2 is a cashier. Finally, from the fact that for all y_2, if y_2 makes tea, then y_2 is a cashier, and that there is at least one y_2 for which if y_2 were a cashier, then y_2 is climbing a mountain we can infer that there is at least one y_2 for which if y_2 makes tea, then y_2 is climbing a mountain. Therefore, the answer is yes.