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A store recently released a new line of alarm clocks that emits a smell to wake you up in the morning. The head of sales tracked buyers' ages and which smells they preferred. Bacon Cinnamon 4 3 Under 13 years old A teenager 3 3 What is the probability that a randomly selected buyer is under 13 years old given that the buyer purchased a clock scented like cinnamon? Simplify any fractions.

2 Answers

4 votes

Final answer:

The probability that a randomly selected buyer is under 13 years old given that the buyer purchased a clock scented like cinnamon is 1/2 or 50%.

Step-by-step explanation:

The question is asking for the probability that a buyer is under 13 years old given that they purchased a clock scented like cinnamon. To find this probability, we will use the table provided:

  • Bacon: 4 (Under 13 years old), 3 (Teenagers)
  • Cinnamon: 3 (Under 13 years old), 3 (Teenagers)

From the table, we see that there are 3 buyers under 13 years old who preferred the cinnamon scent, and there are a total of 3 (Under 13 years old) + 3 (Teenagers) = 6 buyers who chose the cinnamon scent. We can calculate the conditional probability with the formula P(A|B) = P(A ∩ B) / P(B).

In this case:

  • P(A) is the probability that a buyer is under 13 years old.
  • P(B) is the probability that a buyer chose the cinnamon scent.
  • P(A ∩ B) is the probability that a buyer is under 13 years old and chose the cinnamon scent.

The probability P(A ∩ B) is 3 out of the total number of cinnamon buyers, which is 6, so P(A ∩ B) = 3/6. Now, since P(B) is the scenario that we know a buyer chose the cinnamon scent, P(B) is actually 1 (since it is given that the buyer chose cinnamon). Therefore, the probability that a buyer is under 13 years old given that they purchased a clock scented like cinnamon is P(A|B) = P(A ∩ B) / P(B) = (3/6) / 1 = 1/2 or 50%.

User Webwesen
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4 votes

Let's call event A buyers under 13 years old, and event B is a clock scented like cinnamon.

First, we find the probability of A and B


P(A\cap B)=P(A)\cdot P(B)=(7)/(13)\cdot(6)/(13)=(42)/(169)

Then, we use the conditional probability formula to find the probability of A given B.


P(A|B)=(P(A\cap B))/(P(B))=((42)/(169))/((6)/(13))=(42\cdot13)/(169\cdot6)=(7)/(13)

Hence, the probability of A given B is 7/13.

User Coryan
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