Consider the following premises. For all y_1, y_1 will play squash if and only if y_1 will go running. For all y_1, y_1 will go running if and only if y_1 will play squash. Can we infer the following from them? If we can, name the inference rule being used: For all y_1, y_1 will go running if and only if y_1 will play squash.
That is one of the premises. Therefore, the answer is yes.