A survey of 539 adults aged 18-24 year olds was conducted in which they were asked what they did last Friday night. It found:
189 watched TV
163 hung out with friends
29 watched TV and ate pizza, but did not hang out with friends
49 watched TV and hung out with friends, but did not eat pizza
36 hung out with friends and ate pizza, but did not watch TV
30 watched TV, hung out with friends, and ate pizza
60 did not do any of these three activities
How may 18-24 year olds (of these three activities) only ate pizza last Friday night?
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