A bag contains 4 red, 3 yellow and 2 purple discs. A disc is taken, at random, from the bag and is not replaced. A second disc is then taken, at random, from the bag. Calculate the probability that the two discs taken from the bag are different colours?
please help
please help
1 Answer
Explanation:
The first thing to do is to convert these possibilities into a tree diagram, like the one below which I did in Word:
Where
To find the probability of 2 discs being chosen that are different colours, we simply subtract the probabilities that both colours are the same from 1. This means we must find
From the diagram, we see
We also see
and
Next we add all these probabilites together to get
Since the probabilities of getting the same colour are complementary to getting different colours, we can use the rule
https://www.ck12.org/probability/complement-rule-for-probability/lesson/Complement-Rule-for-Probability-ADV-PST/
Therefore,
I hope I helped!