Answer:
20%
Explanation:
Probability is essentially: (# times a specific event can occur) / (# times any event can occur)
Here, the specific event is choosing a green marble. Since there are 4 green marbles, there are 4 ways the specific event can occur so the numerator is 4. Since there are a total of 20 marbles, there are 20 ways that any event can occur, so the denominator is 20. Now, our probability is:
4 / 20 = 1 / 5
To convert this to percent, simply multiply 1/5 by 100: (1/5) * 100 = 20%
Hope this helps!