Nikolai has a jar filled with 120 marbles. he has 72 red marbles, 17 blue marbles, 13 green marbles, and 18 purple marbles. what is the probability that he will randomly select a blue marble, without replacement, and then a purple marble from the jar

To find the probability of both of these occurring, you will multiply the probability of choosing a blue marble by the probability of choosing a purple marble (with no replacement after the first one).

Probability of choosing a blue marble: 17/120

Probability of choosing a purple marble: 18/119

17/120 x 18/119 = 3/140

You will have a 3/140 chance of both of these occurring.