If AA and BB are two events such that P(A∩B)=0.1P(A \cap B)=0.1, and P(A∣B)P(A \mid B) and P(B∣A)P(B \mid A) are the roots of the equation 12x2−7x+1=012x^2-7x+1=0, then the value of P(A‾∪B‾)P(A‾∩B‾)\frac{P(\overline{A} \cup \overline{B})}{P(\overline{A} \cap \overline{B})} is:

Answer: 2.252.25

Step-by-step solution

Step 1: Find the roots of the quadratic equation

The problem states that P(A∣B)P(A \mid B) and P(B∣A)P(B \mid A) are the roots of the quadratic equation 12x2−7x+1=012x^2-7x+1=0. We can find these roots by factoring the quadratic equation or using the quadratic formula.

Step 2: Identify conditional probabilities

From the definition of conditional probability, we know that P(A∣B)=P(A∩B)P(B)P(A \mid B) = \frac{P(A \cap B)}{P(B)} and P(B∣A)=P(A∩B)P(A)P(B \mid A) = \frac{P(A \cap B)}{P(A)}. We are given P(A∩B)=0.1P(A \cap B) = 0.1. Using the roots found, we can set up equations to find P(A)P(A) and P(B)P(B).

Step 3: Calculate P(A)P(A) and P(B)P(B)

Using the conditional probability formulas and the given P(A∩B)P(A \cap B), we can calculate the individual probabilities P(A)P(A) and P(B)P(B).

Step 4: Calculate P(A∪B)P(A \cup B)

We use the formula for the probability of the union of two events to find P(A∪B)P(A \cup B).

Step 5: Calculate P(A‾∪B‾)P(\overline{A} \cup \overline{B}) and P(A‾∩B‾)P(\overline{A} \cap \overline{B})

Using De Morgan's laws, we know that P(A‾∪B‾)=P(A∩B‾)P(\overline{A} \cup \overline{B}) = P(\overline{A \cap B}) and P(A‾∩B‾)=P(A∪B‾)P(\overline{A} \cap \overline{B}) = P(\overline{A \cup B}). We can then use the complement rule P(E‾)=1−P(E)P(\overline{E}) = 1 - P(E) to find these values.

Step 6: Calculate the final ratio

Finally, we substitute the calculated values into the required ratio to find the answer.

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