Consider the following premises. Elisabeth is an office clerk if and only if Sarah is drinking water. Elisabeth is an office clerk or Elisabeth is a soldier. Barbara is working. If Elisabeth were a soldier, then Sarah is drinking water. Can we infer the following from them? If we can, name the inference rule being used: Sarah is drinking water and Barbara is working.
 From the fact that Elisabeth is an office clerk if and only if Sarah is drinking water we can infer that if Elisabeth were an office clerk, then Sarah is drinking water via biconditional elimination. From the fact that if Elisabeth were an office clerk, then Sarah is drinking water, that if Elisabeth were a soldier, then Sarah is drinking water, and that Elisabeth is an office clerk or Elisabeth is a soldier we can infer that Sarah is drinking water via disjunction elimination. Finally, from the fact that Sarah is drinking water, and that Barbara is working we can infer that Sarah is drinking water and Barbara is working via conjunction. Therefore, the answer is yes.