A box contains 2 blue marbles, 5 black marbles, and 2 orange marbles. If one marble is chosen without looking, what is the probability that it is blue?
- 2 blue marbles
- 5 black marbles
- 2 orange marbles
Choose the best answer.
Note
For basic probability, compare the number of favorable outcomes with the total number of equally likely outcomes.
- Count the favorable outcomes first: there are 2 blue marbles.
- Then count all possible outcomes: 2 + 5 + 2 = 9.
- Probability means favorable outcomes divided by total outcomes, so the probability is 2/9, which simplifies to 2/9.
The correct answer is 2/9. This matches the calculation or definition, so students should focus on the reasoning rather than only memorizing the final value.