Given that:
• 844 drank alcohol regularly.
• 626 smoked cigarettes.
,
• 200 used illegal drugs.
,
• 397 drank alcohol regularly and smoked cigarettes.
,
• 115 drank alcohol and used illegal drugs.
,
• 118 smoked cigarettes and used illegal drugs.
• 91 engaged in all three behaviors.
• 169 engaged in none of these behaviors.
You can identify that you must add these values:
In order to find the total number of students that were surveyed, you need to subtract the other values from the Sum obtained above:
Hence, the answer is: