A bag contains 5 red marbles and 3 yellow marbles. What is the probability of drawing a red marble, then replacing that marble, then drawing red marble again on the second pick?

Answer 1

The probability of drawing a red marble on the first pick is 5/8 because there are 5 red marbles out of 8 total marbles.

After you put that marble back into the bag, the probability of drawing a red marble on the second pick is also 5/8 because there are still 5 red marbles out of 8 total marbles.

So the probability of both events happening, because they are independent events, is the probability of the first multiplied by the probability of the second.

So P(Picking 2 red marbles) is 5/8•5/8 = 25/64