Question

МНЕ СРОЧНО НУЖНО ПОМОГИТЕ ((( В коробке лежат белые и черные шары. Число белых шаров на два меньше числа черных. Сколько белых шаров нужно добавить в коробку, чтобы вероятность того, что наугад извлечённый шар будет белым, равнялась бы 2/3? ДАМ 40 БАЛЛОВ

Answer 1

Ответ:

Я не думаю что моя ответ правильно но я скажу что нужно 3-2=1 3+1=4 3×4=12

Пошаговое объяснение:

Я не знаю это правильно или нет!!!

Answer 2

Problem Analysis

In this problem, we are given a box containing white and black balls. The number of white balls is two less than the number of black balls. We need to determine how many white balls should be added to the box so that the probability of randomly selecting a white ball is equal to 2/3.

Solution

Let's assume the number of black balls in the box is B. According to the problem, the number of white balls is two less than the number of black balls, so the number of white balls is B - 2.

To find the probability of randomly selecting a white ball, we need to divide the number of white balls by the total number of balls in the box. The total number of balls is the sum of the number of white balls and the number of black balls:

Total number of balls = Number of white balls + Number of black balls

Let's denote the total number of balls as T.

So, we have the equation:

T = (B - 2) + B

Simplifying this equation, we get:

T = 2B - 2

Now, we can calculate the probability of randomly selecting a white ball:

Probability of selecting a white ball = Number of white balls / Total number of balls

Substituting the values, we get:

Probability of selecting a white ball = (B - 2) / (2B - 2)

According to the problem, this probability should be equal to 2/3. So, we can set up the equation:

(B - 2) / (2B - 2) = 2/3

To solve this equation, we can cross-multiply:

3(B - 2) = 2(2B - 2)

Simplifying this equation, we get:

3B - 6 = 4B - 4

Bringing the terms with B to one side and the constants to the other side, we get:

4 - 6 = 4B - 3B

Simplifying further, we get:

-2 = B

Therefore, the number of black balls in the box is -2. However, since the number of balls cannot be negative, this solution is not valid.

Based on the given information, it seems that there might be an error or inconsistency in the problem statement. Please double-check the problem and provide any additional information if available.