How to find out the audience size?

Question

Mathematics

There is an audience of unknown size.
We made a test with a picture, in a simplified form it can be formulated as follows:

We select 100 random people.
Then we reselect 100 random people.
We find that 25% of the people were chosen twice.

After some time, we choose another 100 random people, and find that 15% of the people were chosen either the first time, or the second time, or both.

You need to know the approximate size of the audience.