John has seven red marbles and three blue marbles in a bag. He removes a marble at random, records the color, puts it back, and then repeats this process until he has withdrawn six marbles. What is the probability that **exactly** three of the marbles that he removes are red? Express your answer as a decimal rounded to the nearest thousandth.

Also an explanation is more helpful than just an answer, I would appreciate it if you took the extra time to help :)

viola Jun 29, 2021