13 Bag A contains 3 black discs and 2 white discs only. Initially Bag B is empty. Discs are removed at random from bag A, and are placed in bag B, one at a time, until all 5 discs are in bag B.
- Write down the probability that the last disc that is placed in bag B is black.
- Find the probability that the first disc and the last disc that are placed in bag B are both black.
- Find the probability that, starting from when the first disc is placed in bag B , the number of black discs in bag B is always greater than the number of white discs in bag B.