Bag $A$ contains 6 red marbles, 5 blue marbles and 1 green marble.
Bag $B$ contains 5 red marbles and 3 blue marbles.
A marble is selected at random from bag $A$ and then transferred to bag $B$.
A marble is now selected at random from bag $B$.
(a)[3]
Draw a tree diagram to show this information, and write the probability on every branch.
(b)[2]
Find the probability that both marbles selected are the same colour.
(c)[3]
Find the probability that the marble taken from bag $A$ is blue, given that the marble taken from bag $B$ is blue.
Worked solution & mark scheme
This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Bag A branches have the correct structure and probabilities.” …