Since the random sample contained 125 out of 500 people who voted for the dog park that is about 25%. since 25% of 500 is 125. If we scale that up to 25% of 3500 it would be 8750 people.
Out of a group of 500 from the 35,000, 125 people wanted a dog park. So find out how many groups of 500 are in 35,000. Which is 70 groups of 500. Since there's 70, you multiply 70 groups by 125
