Answer:
12/155
Step-by-step explanation:
<u>Total number of cookies:</u>
<u>Probability of getting a peanut butter cookie at first attempt is 9 out of 31:</u>
<u>Probability of getting a peanut butter cookie at second attempt is 8 out of 30 as one already taken and the total number has changed as well:</u>
<u>Probability of getting 2 peanut butter cookies is the product of each probability we got above:</u>