The number of beers in 5 liters would depend on the size of the beer. Since cans have less beer in them than bottles generally, there would be more cans in 5 liters than there would be bottles. To...
If by a beer you mean an American standard 12 ounce beer (can or bottle) then there are 2.81783523 beers per liter
one. The mass might be different but the volume remains the same
12 fl oz(US) = 0.354882 L
8.4 and because you cannot get a half beer, the answer is 8.