Question

A survey found that 12 out of every 15 people in the united States prefer eating at a restaurant over cooking at home. if 400 people selected eating at a restaurant on the survey, how many people took the survey

Answer 1

First we simplify 12 out of every 15 people: $\frac{12}{15}}: \frac{3}{3}= \frac{4}{5}}$. $\frac{4}{5}}= \frac{400}{x}= \frac{4*100}{5*100}= \frac{400}{500}}$. Now we do this: $\frac{30}{2hours}= \frac{30:2}{2:2}= \frac{15}{1hour}$. Therefore, she charges $15 per hour, but for 5 hours it would be $75 because $15*5=$75. But, your answer is 500 people took the survey. Hoped I helped. :)

Answer 2

500 people took the survey.

12 out of 15 people is 80% of the population.  12/15 = 0.80
Thus, 80% of the population prefers eating in the restaurant.
 
If 400 represents the people who prefers eating in the restaurant; then, 400 is the 80% of the population. To get the total population or 100%, we must divide 400 by 0.80 or 80%

400 / 0.80 = 500 people.

Out of the 500 people, 400 selected eating in the restaurant while the remaining 20% of the population or 100 people selected cooking at home.