Question

Rhianna buys a bag of cookies that contains 7 chocolate chip cookies, 9 peanut butter cookies, 7 sugar cookies, and 7 oatmeal cookies. What is the probability that Rhianna reaches in the bag and randomly selects an oatmeal cookie from the bag, eats it, then reaches back in the bag and randomly selects a chocolate chip cookie?

Answer 1

To find the probability that Rhianna selects an oatmeal cookie first and then a chocolate chip cookie, we need to find the probability of each event separately and then multiply them together.

Step-by-step explanation:

To find the probability that Rhianna selects an oatmeal cookie first and then a chocolate chip cookie, we need to find the probability of each event separately and then multiply them together.

1. The probability of selecting an oatmeal cookie first is the number of oatmeal cookies divided by the total number of cookies: 7 oatmeal cookies / (7 + 9 + 7 + 7) total cookies = 7/30.
2. After Rhianna selects and eats the oatmeal cookie, there will be 6 oatmeal cookies left in the bag, and the total number of cookies will be reduced to 29.
3. The probability of selecting a chocolate chip cookie from the remaining cookies is the number of chocolate chip cookies divided by the total number of remaining cookies: 7 chocolate chip cookies / 29 total cookies = 7/29.

To find the probability of both events happening together, we multiply the probabilities: (7/30) * (7/29) = 49/870.