There are 3 purple buttons and 6 red buttons in a bag. One button is selected at random. What is the probability of NOT selecting a red button?
- 3 purple buttons
- 6 red buttons
Choose the best answer.
Note
For a “not” event, count the outcomes outside the named event. This is the complement of the event.
- The complement of selecting red is selecting any other color.
- There are 3 non-red buttons out of 9 total buttons.
- So the probability is 3/9 = 1/3.
- A complement probability can also be found by doing 1 minus the probability of the event.
The correct answer is 1/3. This matches the calculation or definition, so students should focus on the reasoning rather than only memorizing the final value.