LET’S TRY ONE
A bag has 2 red and 3 blue counters. One is selected without looking, with each counter equally likely. What is the probability of red?
There are 2 red counters among 5 equally likely counters.
Learning steps & teaching tips
Represent favorable outcomes as a fraction of equally likely outcomes.
- State what is equally likely and count the entire sample space.
- Work through the example. Explain how its evidence supports the answer.
- Try a new question; use the explanation to check your thinking.
Try it together
Write or draw your own example with different numbers. Solve it, then ask a partner to check the method as well as the answer.
State what is equally likely and count the entire sample space.