Well, why did that occur? Well, this can be explained by Boyle's Law and I'll show you in a second. Well, this equation can be rearranged in this format if we're dealing with two different sets of conditions. Notice that p times V will always give you a constant when you're talking about the same temperature and the same number of mole. So if I have one set of conditions p one times v one, that will give me a constant. And if I have the second set of conditions p two times v two, it will give me the same constant, right?