To determine the probability that Kadeesha pulls out either a strawberry or a cherry chew from her bag, we can analyze the situation.
Since the bag contains 10 strawberry chews and 10 cherry chews, there are a total of 20 chews in the bag. When she reaches in without looking, she can pull out either type of chew.
Since both types of chew are present in the bag, it is certain that she will pull out either a strawberry or a cherry chew.
Therefore, the correct answer is:
certain