Question

Из класса в котором учатся 13 мальчиков и 12 девочек, выбирают по жребию одного дежурного. Какова вероятность, что это будет мальчик? (как решить?)

Answer 1

Всех исходов (n) мальчики + девочки, потому что можно выбрать и девочку и мальчика

13+12=25
n= 25


Благоприятные исходы (m) , нам надо мальчика выбрать. Считаем только мальчиков.

m=13

Формула Р=m/n

Вероятность Р=m/n=13/25= 0,52

Ответ: вероятность выбрать дежурным мальчика 0,52.

Answer 2

Problem Analysis

In a class of 13 boys and 12 girls, one student is chosen at random to be the monitor. We need to find the probability that the monitor will be a boy.

Solution

To find the probability, we need to determine the number of favorable outcomes (the number of ways to choose a boy as the monitor) and the total number of possible outcomes (the total number of students in the class).

The number of favorable outcomes is the number of boys in the class, which is 13.

The total number of possible outcomes is the total number of students in the class, which is the sum of the number of boys and girls, i.e., 13 + 12 = 25.

Therefore, the probability of choosing a boy as the monitor is given by:

Probability = Number of favorable outcomes / Total number of possible outcomes

Probability = 13 / 25

Simplifying the fraction, we get:

Probability = 0.52

So, the probability that the monitor will be a boy is 0.52.

Answer

The probability that the monitor will be a boy is 0.52.