Question

i dont know the answer to this question Mark wants to eat one last cookie from the cookie jar. In the jar there are 5 chocolate chip cookies, 6 peanut butter cookies, and 9 oatmeal cookies. He will randomly select one cookie from the jar. What is the probability that Mark will NOT pick a peanut butter cookie?

Answer 1

so the sample space will be simply all the cookies in the jar, namely 5 + 6 + 9 = 20.

the probability that Mark will NOT pick a Peanut Butter one hmm, that means that Mark will pick either a Chocolate Chip or an Oatmeal one, now this is an OR case so that means sum. so what are the chances Mark will pick either one? P(Chocolate) + P(Oatmeal)

`\stackrel{P(Chocolate)}{\cfrac{5 }{20}}~~ + ~~\stackrel{P(Oatmeal)}{\cfrac{9}{20}}\implies \cfrac{5+9}{20}\implies \cfrac{14}{20}\implies \cfrac{7}{10}\implies 0.7~\hfill \text{\LARGE 70\%}`