Answer:
200
Step-by-step explanation:
Total number of people surveyed = 800
Number of people who like rock = 700
Number of people who like country = 300
Let the number of people who like both genres = x
Among the 700 people who like rock there are some people who like country as well likewise among the 300 people who like country there are some people who like rock as well. So those who like both genres are being counted twice, once in 700 and once in 300. So if we subtract the number of people who like genres from 700 or 300 we will get the total number of people as shown below:
i.e.
800 = 700 + 300 - x
x = 700 + 300 - 800
x = 200
This means, 200 people like both genres.
From we can also say 500 people like only rock, 100 people like only country and 200 people like both.
