Without knowing the number of bands or the colors, it is impossible to determine the exact probability. However, we can describe the probability as the ratio of the number of elastic bands of a particular color to the total number of elastic bands in the bag.
For example, if there are 5 red elastic bands out of a total of 20, the probability of selecting a red elastic band is 5/20 or 25% (expressed as a fraction). We can also express this as a decimal (0.25) or a ratio (1 in 4).
The word or phrase commonly used to describe this probability is "chance" or "likelihood." We can say that there is a chance or likelihood of selecting a particular color elastic band from the bag.