Math Problem Statement

Брошены монета и игральная кость одновременно. Проверить, зависимы ли события A = {на монете выпал «герб»} и B = {на кости выпало число очков, кратное трем}.

Solution

The problem presented in the image is asking to determine whether the events AA and BB are dependent or independent.

  • Event A: The coin shows "герб" (tails).
  • Event B: The dice shows a number divisible by 3.

Analyzing Independence

To check if the two events are independent, we use the standard rule of probability:

P(AB)=P(A)P(B)P(A \cap B) = P(A) \cdot P(B)

where:

  • P(A)P(A) is the probability of event AA,
  • P(B)P(B) is the probability of event BB,
  • P(AB)P(A \cap B) is the probability of both events happening together.

Step 1: Calculating P(A)P(A)

Since we are tossing a coin, the probability of getting "tails" (event AA) is:

P(A)=12P(A) = \frac{1}{2}

Step 2: Calculating P(B)P(B)

The dice has 6 sides, and the numbers divisible by 3 are 3 and 6. Therefore, there are two favorable outcomes for event BB:

P(B)=26=13P(B) = \frac{2}{6} = \frac{1}{3}

Step 3: Calculating P(AB)P(A \cap B)

The coin and dice are tossed simultaneously. The probability of both getting "tails" (event AA) and a number divisible by 3 on the dice (event BB) is:

P(AB)=P(A)P(B)=1213=16P(A \cap B) = P(A) \cdot P(B) = \frac{1}{2} \cdot \frac{1}{3} = \frac{1}{6}

Step 4: Checking Independence

Now, check if P(AB)=P(A)P(B)P(A \cap B) = P(A) \cdot P(B). Since:

P(AB)=16P(A \cap B) = \frac{1}{6}

and:

P(A)P(B)=16P(A) \cdot P(B) = \frac{1}{6}

The two events AA and BB are independent because the condition for independence holds true.

Conclusion

The correct answer is: Независимы (Independent).

Would you like more details or have any questions?

Here are some related questions to deepen your understanding:

  1. What is the formula for conditional probability?
  2. How can we calculate the probability of a union of two events?
  3. What does it mean if two events are dependent?
  4. How would the answer change if the events involved rolling two dice instead of one?
  5. Can two mutually exclusive events ever be independent?

Tip: For two events to be independent, knowing the outcome of one event should not affect the probability of the other event occurring.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Probability
Independent Events
Dependent Events

Formulas

P(A ∩ B) = P(A) * P(B)
P(A) = 1/2
P(B) = 2/6 = 1/3

Theorems

Independence of Events Theorem

Suitable Grade Level

Grades 10-12