Consider the following premises. If Patricia drinks water, then it is sunny. If it is sunny, then Patricia is driving a car. For all x_15, x_15 will drive a car if and only if x_15 will drink water. Can we infer the following from them? If we can, name the inference rule being used: If it is sunny, then Patricia is drinking water.
 From the fact that for all x_15, x_15 will drive a car if and only if x_15 will drink water we can infer that for all x_15, if x_15 drives a car, then x_15 is drinking water via universal biconditional elimination. From the fact that for all x_15, if x_15 drives a car, then x_15 is drinking water we can infer that if Patricia drives a car, then Patricia is drinking water via universal instantiation. Finally, from the fact that if it is sunny, then Patricia is driving a car, and that if Patricia drives a car, then Patricia is drinking water we can infer that if it is sunny, then Patricia is drinking water via transitivity. Therefore, the answer is yes.