[填空题]
The first two characters of a faaq4 5ax:k3s student ID number is composed by thel8h+ pfuzjn /8o:)gn f/hk w8y following rul8n/gp8jy hk o:uh fw)nf/l8+z es:
- one letter is chosen from student's first name at random;
- one digit is chosen from student's date of birth at random (dd/mm/yyyy).
Bob Stewart was born on the 12th of January, 2001(12/01/2001). Find the probability that
1. Bob's ID starts with "B1".
2. Bob's ID starts with "B" or its second character is "2".
3. Bob's ID starts with "O" given that the second character is not 0 . ≈