The answer is a probability of 0.1875 or 18.75%.

There are three yellow marbles and there are 16 marbles in total. Therefore you would take three divided by 16 to get the answer. This is 0.1875. If you multiply 0.1875 by 100 to get the percentage you will find that there is an 18.75% chance that you will get a yellow marble out of the box when selecting at random.

- To calculate the probability you need to know the correct formula.

There are three yellow marbles and there are 16 marbles in total. Therefore you would take three divided by 16 to get the answer. This is 0.1875. If you multiply 0.1875 by 100 to get the percentage you will find that there is an 18.75% chance that you will get a yellow marble out of the box when selecting at random.

- If you want to know the probability of gaining a blue marble it is 0.3125 or 31.25%.

- There are eight green marbles. This means you can do the probability calculation in your head because there are 16 marbles total. The answer is 0.5 or 50%.