If a bag contains 4 red, 6 blue, and 5 green marbles, what is the probability of drawing a green marble on one draw?

If a bag contains 4 red, 6 blue, and 5 green marbles, what is the probability of drawing a green marble on one draw?

• A. 1/4
• B. 2/5
• C. 1/3
• D. 5/9

Answer: (C)

Probability of a single draw equals the number of favorable outcomes over the total number of outcomes. Here, there are 4 red, 6 blue, and 5 green marbles, for a total of 15 marbles. The favorable outcomes are the green marbles, which are 5. So the probability is 5/15, simplified to 1/3. The other fractions would come from different numbers of greens or a different total, so they don’t describe this bag.

Probability of a single draw equals the number of favorable outcomes over the total number of outcomes. Here, there are 4 red, 6 blue, and 5 green marbles, for a total of 15 marbles. The favorable outcomes are the green marbles, which are 5. So the probability is 5/15, simplified to 1/3. The other fractions would come from different numbers of greens or a different total, so they don’t describe this bag.