Answer:
0.0286 or 2.86%
Step-by-step explanation:
The total number of people that have werewolfism is 21,000.
Of those 21,000, 600 also have vampirism, while the remaining 20,400 do not. Therefore, the probability that someone has vampirism, given that they have werewolfism is:
The probability is 0.0286 or 2.86%.