Page 165 - TB_6B

Activity 3 Dependent Events

If the outcome of the 1st event affects the 2nd event, the events are called
dependent events.

A and B are dependent events.
P(A and B) = P(A) P(B after A)

There are 1 red marble(R), 1 yellow marble(Y), and 2 blue marbles(B) in the
bag.
Find the probability of pulling out a blue marble after pulling out a yellow
marble without putting it back in the bag.

1st event

The probability of pulling out a yellow marble from the bag is B
RY
P(Y)= 1 .
4 B

2nd event

For the 2nd event, there are 3 marbles left in the bag.

The probability of pulling out a blue marble after pulling out a B
R
yellow marble is
B
P(B) = 2 .
3

P(Y and B) = P(Y) P(B after Y)= =.

154