Question

В коробке 3 синих и 7 красных шариков. Наугад извлекается один шарик, затем второй. Найти вероятность того, что первый шарик — красный, а второй — синий.

Answer 1

Всего шаров 10,поэтому вероятность что первый шарик будет красный будет 7/10=0,7,а красный 3/10=0,3

Answer 2

Problem Analysis

We are given a box containing 3 blue balls and 7 red balls. We need to find the probability of drawing a red ball first and then a blue ball.

Solution

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

The total number of possible outcomes is the total number of balls in the box, which is 10.

The number of favorable outcomes is the number of ways we can draw a red ball first and then a blue ball. Since there are 7 red balls and 3 blue balls, the number of favorable outcomes is 7 * 3 = 21.

Therefore, the probability of drawing a red ball first and then a blue ball is 21/10.

Answer

The probability of drawing a red ball first and then a blue ball is 21/10.