Answer:
The disc jockey can simply run a what is called a random experiment. In this experiment, she takes all the songs, and defines the probability of a particular song being played.
Explanation:
More specifically, in her random experiment, the DJ has a specific number of songs in total. Let's assume that she has 9 songs in total: 3 rock songs, 3 country songs, and 3 pop songs. We can assume this because the question says that she has an equal number of songs per genre.
The probability of the first song being a country song is therefore 1/9, because the country song is 1 among 9 songs in total.
The probability of the second song also being a country song is 1/8, because now, there are only 8 songs remaining,
Finally, the probability of the third song also being a country song is 1/7, again, because now, there are only 7 songs remaining.
Now, to find the probability of the first three songs all being country song, we multiply the above probabilities.
1/9 * 1/8 * 1/7 = 1/504 or 0.19%.
As we can see, the probability is extremely low.