Please answer both.

A computer system uses passwords that contain exactly 5 characters, and each character is 1 of the 3 lowercase letters (a, b, c) or 3 upper case letters (A, B, C) or the 5 odd digits (1,3,5,7,9). Let denote the set of all possible passwords, and let A and B denote the events that consist of passwords with only letters or only integers, respectively. Determine the probability that a password contains all lowercase letters given that it contains only letters. Report the answer to 3 decimal places. A computer system uses passwords that contain exactly 4 characters, and each character is 1 of the 3 lowercase letters (a,b,c) or 3 upper case letters (A,B,C) or the 5 odd digits (1,3,5,7,9).. Let denote the set of all possible passwords, and let A and B denote the events that consist of passwords with only letters or only integers, respectively. Determine the number of passwords for AB. Report the exact number