There are 50 red balls and 30 blue balls in a box. If you randomly pick one ball without looking, what is the probability of picking a green ball?
The probability of picking a green ball is 0.

Here's the explanation:
1. The box contains only red and blue balls, with 50 red balls and 30 blue balls.
2. There are no green balls in the box.
3. Since there are no green balls to pick from, the probability of picking a green ball is 0.