That is, is there an open cover of $\mathbb{R}P^n$ by $n$ sets homeomorphic to $\mathbb{R}^n$?

I came up with this question a few years ago and I´ve thought about it from time to time, but I haven´t able to solve it. I suspect the answer is negative but I´m not very sure. Also, is there an area of topology which studies questions like this one?