Answer:
Probability = 0.500
Step-by-step explanation:
If it is given that the reader is a teen, we have a total of 80 readers, where 40 of those readers have Rowling as their favorite.
So the probability that the reader's favorite is Rowling given that the reader is a teen is the number of teen readers that have Rowling as favorite (40) over the total number of teen readers (80)
Probability = 40 / 80 = 0.500
