) Suppose you have n ∈ N different posters. For each poster, you can choose to either hang it on your wall or put it in the closet. Depending on how you choose, you’ll end up with no posters on the wall, with just some posters on the wall, or maybe even with all posters on the wall. How many possible sets of posters can you have on your wall? Note that we are not interested in how you arrange your p