N anonymous survey of college students was taken to determine behaviors regarding alcohol, cigarettes, and illegal drugs. The results were as follows: 865 drank alcohol regularly, 667 smoked cigarettes, 205 used illegal drugs, 420 drank alcohol regularly and smoked cigarettes, 113 drank alcohol regularly and used illegal drugs, 117 smoked cigarettes and used illegal drugs, 95 engaged in all three behaviors, and 318 engaged in none of these behaviors.
a) How many students were surveyed?
nothing