SOLUTION:
If a marble is chosen at random and we are told the marble is red what is the probability that has the number 2 on it;
We have only one red marble out of eight red marbles that have number two on it.

(b) If the first marble is replaced, and another marble is chosen at random if we are told that the marble has number 1 on it, what is the probability that the marble is red;
We have two marbles having 1 (i.e one blue and one red)

r