Question

Bз урны в которой находятся 3 черных и 7 белых шаров вынимают 2 шара какова вероятность того, что оба шара будет черными?

Answer 1

Вынимают по очереди? Если да, то
3/10 вытащить первый * 2/9 вытащить второй
3/10 * 2/9 = 1/15

Answer 2

Calculating the Probability of Drawing Two Black Balls

To calculate the probability of drawing two black balls from an urn containing 3 black and 7 white balls, we can use the concept of conditional probability.

The probability of drawing the first black ball can be calculated using the formula: $$P(B_1) = \frac{3}{10}$$ This is because there are 3 black balls out of a total of 10 balls in the urn.

After drawing the first black ball, the probability of drawing the second black ball can be calculated using the formula: $$P(B_2|B_1) = \frac{2}{9}$$ This is because there are 2 black balls remaining out of a total of 9 balls after the first black ball has been drawn.

Calculating the Total Probability

To find the total probability of drawing two black balls, we multiply the individual probabilities: $$P(B_1) \times P(B_2|B_1) = \frac{3}{10} \times \frac{2}{9} = \frac{1}{15} \approx 0.067$$

Therefore, the probability of drawing two black balls from the urn is approximately 0.067, or 6.7%.