marvel confusion

Question

Barrels of Marbles Two barrels each contain 1000 marbles. The blue barrel has 1000 blue marbles; the red barrel has 1000 red marbles. Ten marbles are removed from the blue barrel, placed in the red barrel, and mixed in. Then ten marbles are removed from the red barrel at random, placed in the blue barrel, and mixed in. After these two steps are repeated two more times, are there ... a) more blue marbles in the red barrel than there are red marbles in the blue barrel? b) more red marbles in the blue barrel than there are blue marbles in the red barrel? c) the same number of blue marbles in the red barrel as there are red marbles in the blue barrel? OR d) There is no way to determine whether there are more blue marbles in the red barrel or more red marbles in the blue barrel.

Answer 1

c) it doesn't matter how many times you repeat this procedure, c) is the answer

look at the blue barrel; if there are 50 red marbles in the blue barrel, then where are the 50 blue marbles the red marbles displaced ? they are in the red barrel

each barrel will contain the same number of the opposite color marbles as long as each barrel contains 1000 marbles