There are 7 yellow counters and 3 red counters in a bag. One counter is selected at random. What is the probability of NOT selecting a yellow counter?
- 7 yellow counters
- 3 red counters
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 yellow is selecting any other color.
- There are 3 non-yellow counters out of 10 total counters.
- So the probability is 3/10 = 3/10.
- A complement probability can also be found by doing 1 minus the probability of the event.
The correct answer is 3/10. This matches the calculation or definition, so students should focus on the reasoning rather than only memorizing the final value.