1. Note 6: Conditional Probability
The probability of subsequent events occurring
depends on the occurrence (or not) of the first
event.
If the object is put to one side, we call it sampling without replacement.

2. Example: A box of chocolates contains 9 hard centres (H) and 6 soft centres (S). One chocolate is taken at random and eaten, then a second chocolate is taken. Find the probability that: H
Both chocolates have soft centres
One has a hard centre and one has a soft centre H S H S S

3. Page 512
Exercise 16G