Consider the following premises. For all z, if z works, then z is playing squash. For all z, z will work or z will not play squash. Can we infer the following from them? If Richard plays squash, then Richard is working.
 From the fact that for all z, z will work or z will not play squash we can infer that for all z, if z plays squash, then z is working. From the fact that for all z, if z plays squash, then z is working, and that for all z, if z works, then z is playing squash we can infer that for all z, z will play squash if and only if z will work. From the fact that for all z, z will play squash if and only if z will work we can infer that Richard is playing squash if and only if Richard is working. Finally, from the fact that Richard is playing squash if and only if Richard is working we can infer that if Richard plays squash, then Richard is working. Therefore, the answer is yes.