a bag contains 4 red, 2 blue, 6 green, and 8 white marbles. what is the probability of selecting, replacing it and then selecting a red marble?
At a glance this problem seems really hard but it atually is no, replacing the red marble does not affect the overall answer. So, all we have to do is multiply this out:
Pulling a red marble out*Pulling a red marble out
And thus 4/81 is our final answer.