A box contains 7 white marbles, 5 green marbles, and 4 red marbles. If one marble is chosen without looking, what is the probability that it is red?
- 7 white marbles
- 5 green marbles
- 4 red 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 4 red marbles.
- Then count all possible outcomes: 7 + 5 + 4 = 16.
- Probability means favorable outcomes divided by total outcomes, so the probability is 4/16, which simplifies to 1/4.
The correct answer is 1/4. This matches the calculation or definition, so students should focus on the reasoning rather than only memorizing the final value.