Question

Из коробки с двумя белыми и двумя чёрными шарами вынимают, не глядя, два шара. Какова вероятность, что они оба белые?

Answer 1

Чтобы найти вероятность каког -то события, надо число благоприятных исходов разделить на общее количество исходов.
Всего исходов : бб
                         чч
                         бч
                         чб
4 штуки. Благоприятных 1
Р(А) = 1/4 = 0, 25

Answer 2

Problem Analysis

We are given a box with two white balls and two black balls. Two balls are randomly drawn from the box without looking. We need to find the probability that both balls are white.

Solution

To find the probability, we need to determine the total number of possible outcomes and the number of favorable outcomes.

# Total Number of Outcomes

The total number of outcomes is the number of ways we can choose two balls from the four balls in the box. This can be calculated using the combination formula:

Total Number of Outcomes = C(4, 2)

Using the combination formula, we can calculate:

C(4, 2) = 4! / (2! * (4-2)!) = 6

Therefore, there are 6 possible outcomes when two balls are drawn from the box.

# Number of Favorable Outcomes

The number of favorable outcomes is the number of ways we can choose two white balls from the two white balls in the box. Since there are only two white balls, the number of favorable outcomes is:

Number of Favorable Outcomes = C(2, 2)

Using the combination formula, we can calculate:

C(2, 2) = 2! / (2! * (2-2)!) = 1

Therefore, there is only 1 favorable outcome where both balls drawn are white.

# Probability Calculation

The probability of both balls being white is the ratio of the number of favorable outcomes to the total number of outcomes:

Probability = Number of Favorable Outcomes / Total Number of Outcomes

Substituting the values we calculated:

Probability = 1 / 6

Therefore, the probability that both balls drawn are white is 1/6.

Answer

The probability that both balls drawn from the box are white is 1/6.