Okay so the combined gas law equations is PiVi/Ti = PfVf/Ti and you have to plug in what you’re given into the equation, cross multiple and then you have to isolate what you’re looking for. I had chemistry last semester and I’m not sure if I remember much, but I’ll attempt a question :)
I’m quite sure when you’re not given a value, you just consider it to be STP, but I’m not sure. I hope this just gives you an idea of what to do at least. Good luck!!!