A game consists of randomly choosing a bag (labelled 1, 2 or 3) out of a choice
of 100, and then again randomly, picking a ball (red or black) from it.
Each bag has the same total number of balls (10).
a) Complete the tree diagram.
Ball options
Bag options
0.6

-Red
b) Work out the probability that a player
will select a red ball.
0.4
Black
-Red
0.2

0.35
0.45

c) The same player is going to play the
game 200 times consecutively.
How many black balls should he
expect to pick?

0.8
-Red
0.7
3
Black
0.