In my text book, it says that pV=C (Boyle's Law), V/T=C (Charle's Law) and that P/T=C (pressure Law). The problem is that I cannot see how the first two equations combine to give the last one. If I divide the first equation by the second, I get that pT=C, which certainly is not the same as the equation given in my text book. I'm not sure if maybe you cannot combine these two equations because Boyl's law assumes constant temperature but Charle's Law assumes constant pressure? Although I don't see why that would mean you cannot combine them... I'm not sure if I should have posted this here or in classical physics, so I will move it if necessary. Thank you in advance!