if 1/6 of a roll of paper covers 1/4 of a wall, this means that we will need 4/6 of a roll to cover a whole wall, now the question is asking how many rolls will we need to cover 4 walls, we already know that it takes 4/6 to fill one wall so if we add 4/6+4/6+4/6+4/6 we will get 16/6 or 2 4/6
we will need 16/6 or 2 4/6 of rolls of paper to cover 4 walls
