Explanation of the question? Assume that there is an apple supplier that ships apples to grocery stores in
batches of size 20. Suppose that 60% of all such batches contain no rotten
apples, 30% contain one rotten apple, and 10% contain two rotten apples. A
batch is picked, two apples from the batch are randomly selected and inspected, and neither is rotten.
a) What is the probability that zero rotten apples exist in the batch?
b) What is the probability that one rotten apple exists in the batch?
c) What is the probability that two rotten apples exist in the batch?
I am confused about the question here, Should I try to find out P(Rotten=0) and 1 and 2? But then my question is they are already given. Can anyone help me?

The question is conditional probability. i.e. you need to find the probability that this batch has 0 rotten apples, given the fact that you know that 2 out of 20 that was randomly picked wasn't rotten.
i.e.
P(batch_has_0_rotten| 2_out_of_20_was_not_rotten).
The difference is with the extra information. Imagine for example that you had information that 19 apples that picked at random was not rotten, then you have more confidence than the prior 60% that it is a batch with 0 rotten.
You can solve this using bayes theorem.
