statistics problem

There are three TAs at STAT200 Office Hours: Greg, Raul, and Maya. Two students arrive at office hours at different times when the TAs are helping no other students. It is assumed that the students then approach a TA for help at random and independently of one another. Let X and Y be defined as follows: X = # of times Raul is asked for help Y = # of times Maya is asked for help 1. Find the joint probability distribution of X and Y. 2. Find the marginal distribution of X. 3. Find the marginal distribution of Y. 4. Find the expected number of students that will ask Raul for help. 5. Find the expected number of students that will ask Maya for help. 6. Find P(X = 1 | Y = 0). Without using mathematical notation (i.e. in words) what does this probability represent? 7. Given that no students have asked Raul for help, what is the probability that no students have asked Maya for help