A group of friends goes to a restaurant. There are 4 vegetarians, 3 vegans, and 5 meat-eaters. If everyone orders a meal according to their dietary preference, what is the probability that a randomly chosen person will order a vegetarian meal?
Here's the reasoning behind this problem:

1. First, let's find out the total number of people in the group. We have 4 vegetarians, 3 vegans, and 5 meat-eaters, so the total number of people is 4 + 3 + 5 = 12.
2. Next, we need to determine the probability of choosing a vegetarian. Since there are 4 vegetarians in the group, the probability of choosing a vegetarian is 4 out of the total number of people (12).
3. Therefore, the probability of choosing a vegetarian is 4/12.

Final answer: The probability of choosing a vegetarian is 1/3 or approximately 33.33%.