Answer:
7/145
Step-by-step explanation:
We have
9 chocolate chip cookies
7 peanut butter cookies
7 sugar cookies
7 oatmeal raisin cookies.
9+7+7+7 = 30 cookies.
What is the probability that Krystal randomly selects a peanut butter cookie from the bag, eats it, then randomly selects another peanut butter cookie?
Initially, there are 30 cookies, 7 of which are peanut butter cookies. So the probability that Krystal selects a peanut butter from the bag is 7/30.
Suppose she selected the peanut butter cookie. Now there are 29 cookies, of which 6 are peanut butter. So the probability that the second one is a peanut butter cookie is 6/29.
Probability that both are peanut butter cookies:
Multiplication