Step-by-step explanation: its really complicated so ill try my best.
so the say 11 like both coffee and tea so that means that they also added 11 to
the other two sections. so if we take 11 away from 18 we get 7, and that's how many people like coffee and not tea. to get answer c) we need to also subtract 11 from 15, which gets us 4. so we have 11 plus 4 plus 7. and that gets us 22. so 30 subtract 22 gets us 8 so 8 people don't like tea or coffee. 22 is also the answer to a). did you get that? i hope so
