How to calculate probability that something happens to n people out of N people in room? I don’t quite get how to solve this problem:

There are 100 people in the room.  10 of them are suspected spies. We know for sure that 20 out of 100 people in the room are spies. What is the probability that not all 10 suspects in the room are spies (0 out of 10 are spies or 1 out of 10 are spies or 2 out of 10 are spies,..., or 9 out of 10 are spies)?

I don’t understand whether the events of suspected spies are interdependent.
How to solve this problem?

Depends on the accuracy of our suspicion. For example if when we suspect a person to be a spy we are correct 0% of the time, then the probability will be 0. If we are correct 100% of the time, then the probability would be 1.
But intuition tells me the question is asking about the probability of randomly guessing all 10 spies when the true number of spies in the sample of 100 is 20.
In this case we might rephrase this question and make it about balls and urns instead of people and spies. Then it would sound like this:
In the urn there are 100 balls. 20 of them are black and the rest are white. We draw 10 balls from the urn without replacement. What is the probability that all of those balls will be black?
See if you can pick it up and answer from this point.
