Question

В классе 32 двухместные парты. За ними сидят 64 школьника и слушают лекцию. Оказалось, что 75% мальчиков сидят рядом с девочками, а 45% девочек сидят рядом с мальчиками. Сколько в аудитории девочек?

Answer 1

Пусть в классе m мальчиков и d девочек. Очевидно, что количество мальчиков, сидящих с девочками, равно числу девочек, сидящих с мальчиками:
$0.75m=0.45d \\\ 75m=45d \\\ m=0.6d$
Кроме того известно, что всего в классе 64 школьника:
$m+d=64$
Подставляем выражение для m:
$0.6d+d=64 \\\ 1.6d=64 \\\ d= \frac{64}{1.6} =40$
Ответ: 40 девочек

Answer 2

Given Information:

In the classroom, there are 32 two-seater desks, and 64 students are sitting at them listening to a lecture. It is known that 75% of boys sit next to girls, and 45% of girls sit next to boys. We need to determine the number of girls in the classroom.

Solution:

Let's assume the number of boys in the classroom is B and the number of girls is G.

From the given information, we can deduce the following equations:

1. The total number of students in the classroom is 64: B + G = 64

2. 75% of boys sit next to girls: 0.75B = G

3. 45% of girls sit next to boys: 0.45G = B

We can solve this system of equations to find the values of B and G.

From equation 2, we can express B in terms of G: B = (4/3)G

Substituting this value of B into equation 3: 0.45G = (4/3)G

Simplifying: 0.45G = (4/3)G 0.45G - (4/3)G = 0 (0.45 - 4/3)G = 0 (0.45*3 - 4)/3G = 0 (1.35 - 4)/3G = 0 (-2.65)/3G = 0

Since the left side of the equation is negative, the only way for the equation to be true is if G = 0. Therefore, there are no girls in the classroom.

Answer:

There are no girls in the classroom.