Answer:
5.
Explanation:
Given that Nicholas performs an experiment in which he pulls a marble from a bag, and in his experiment, he finds that he is twice as likely to pull a red marble as a blue marble, to determine, if Nicholas pulls 10 red marbles, how many blue marbles does he pull, the following calculation must be performed:
10/2 = X
5 = X
Therefore, Nicholas pulls 5 blue marbles from the bag.