Probability

Some examples of probability


Imagine a bag which contains 3 orange balls, 2 red balls and 5 yellow balls.

If Bob takes a ball at random from the bag - what's the probability that Bob takes an orange ball?

Well, there are 3 orange balls in the bag so Bob has 3 chances of grabbing an orange ball. There are a total of 10 balls in the bag and Bob can take any one of the 10 so there are 10 possible events which can occur.

So, the probability of Bob taking an orange ball is ...



If Bob now takes another ball from the bag - what's the probability he will take another orange ball?

This time, there are 2 orange balls left in the bag so Bob has 2 chances of taking an orange ball. There are a total of 9 balls left in the bag and Bob can take any one of these so there are 9 possible events which can occur.

So, the probability of Bob taking another orange ball is ...