Based on the problem, there are three Friday night activities.
These are:
1. Watching TV
2. Hanging out with friends
3. Eating pizza
When faced with this kind of question, the first step to do is to indicate first the number of people who did all the activities. In this case, there are 44 who watched tv, hung out with friends, and ate pizza. Thus, we have put 44 to the part where the common area of the three circles.
The next step is to indicate the number of people who did "two" activities.
1. Watched tv and ate pizza only = 31
2. Watched tv and hung out with friends only = 33
3. Hung out with friends and ate pizza only = 32
After this, the next step is now to focus on the number of people who only did one activity. Based on the problem, it is reported that:
1. 199 Watched TV but did not indicate if it's watching TV ONLY. To solve how many adults watched tv only, let's subtract the number of adults who did all three activities and who did two activities that include watching tv.
Thus, 199 - 44 - 33 - 31 = 91 adults. Only 91 adults watch TV only.
2. 153 hung out with friends but did not indicate if it's hanging out with friends ONLY. To solve how many adults did this activity only, let's subtract the number of adults who did all three activities and who did two activities that include hanging out with friends.
Thus, 153 - 44 - 33 - 32 = 44 adults. Only 44 adults hung out with friends only.
Now that we are able to determine how many adults did/did not do an activity, let's add it all up and subtract it from the total number of adults included in the survey.
543 - (68 + 91 + 33 + 44 + 31 + 44 + 32) = 543 - 343 = 200.
Therefore, there are 200 adults who ate pizza only.