From the question, we are informed that John wanted to know about the popularity of a particular movie and that he surveyed 20% of the people in 5 different theaters.
This is an unbiased sample. This is because everybody at the theaters have an equal chance of being chosen by John.
Also, it's a simple random sampling. This is because a subset of the entire population is randomly selected.
Basically a proportion so it’d be 1in/300 mi = 3in/x mi cross multiple that out and you get 300•3=x and then just solve for x. the answer should be 900 miles.
