A bucket contains 50 lottery balls numbered 1-50. One is drawn at random. Find each probability.

P(at least 20 | prime number)

For the prime numbers it's 15/50 or 3/10. For it to be at least 20 it's 31/50. For both to happen at the same time it's 7/15.

Step-by-step explanation:

The prime numbers between 1 and 50 are: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43 and 47.

50-19=31 so 31/50