Translation:There are three patients in front of the hospital.
"Hastanenin önünde üç hasta var." Translation: There are three patients in front of the hospital.
"In front of the hospital are three sick people." My (wrong) answer.
Live & learn?
So Hasta can mean patient and sick?
So, "the sick patients are in the hospital" is literally: hastanede hasta hastalar. and: "The patient is sick" is literally hasta hasta.
I think that "patient" doesn't quite do it justice; I believe that the noun usage of hasta is like the German der Kranke, i.e. "the sick one" or "the sick person".
So, a reasonable extension of adjective to noun with the meaning "the X one", "the one who is X", "someone who is X/something that is X".
"The sick patients are in the hospital" would be "hasta hastalar hastanede", I think -- "hastanede hasta hastalar" would be something like "in the hospital, the sick people are sick" or "in the hospital, they are sick people" while "hastanede hasta hastalar var" would be "There are sick sick people in the hospital".