Question

У папы и мамы несколько детей. У каждой девочки поровну братьев и сестер, а у каждого мальчика сестер в два раза больше чем братьев. Сколько всего детей в этом семействе?

Answer 1

Дали добавить ответ.
Пусть братьев x, сестер y.
У каждой девочки x братьев и y-1 сестер. И это одинаковые числа.
x = y - 1
У каждого мальчика x-1 братьев и y сестер, и сестер вдвое больше.
2(x - 1) = y
Решаем систему
$\left \{ {{x=y-1}\atop {2(x-1)=y}} \right.$

$\left \{ {{y=x+1} \atop {y=2(x-1)}} \right.$

$x+1=2x-2$
$x=3;y=x+1=4$

Братьев 3, сестер 4. У каждой девочки 3 брата и 3 сестры, а у каждого мальчика 2 брата и 4 сестры.

Answer 2

Пусть x-братья, y-сестры.
У каждой девочки поровну братьев и сестерзначит, 
y-x=1
а у каждого мальчика сестер в два раза больше чем братьев.значит, 
2x=y
Составим систему уравнений.
$\left \{ {{y-x=1} \atop {2x=y}} \right.$
$\left \{ {{2y-y=2} \atop {x= \frac{y}{2} }} \right.$
$\left \{ {{y=2} \atop {x=1}} \right.$
Ответ: 1 брат, 2 сестры.
По  моему так.

Answer 3

Calculation of the Total Number of Children in the Family

To determine the total number of children in the family, we need to analyze the given information. Let's break it down step by step:

1. Each girl has an equal number of brothers and sisters. 2. Each boy has twice as many sisters as brothers.

Let's assume there are x girls and y boys in the family.

1. Each girl has x-1 siblings (brothers and sisters). This means that the total number of siblings for all the girls in the family is x(x-1). 2. Each boy has 2y sisters and y-1 brothers. This means that the total number of siblings for all the boys in the family is 2y(y-1).

To find the total number of children in the family, we can add the number of girls and boys together:

Total number of children = x + y

Now, let's solve the equations to find the values of x and y.

From the given information: - Each girl has an equal number of brothers and sisters: x(x-1) = x-1 - Each boy has twice as many sisters as brothers: 2y(y-1) = y

Simplifying the equations: - x(x-1) = x-1 can be simplified to x^2 - x = x - 1 - 2y(y-1) = y can be simplified to 2y^2 - 2y = y

Solving the equations: - x^2 - x = x - 1 simplifies to x^2 - 2x + 1 = 0 - 2y^2 - 2y = y simplifies to 2y^2 - 3y = 0

Solving these quadratic equations, we find: - x = 1 (since the equation simplifies to x^2 - 2x + 1 = (x-1)^2 = 0) - y = 0 or y = 3/2

Since the number of children cannot be zero, we can conclude that y = 3/2. Therefore, there are 3/2 boys in the family.

Now, let's calculate the total number of children: Total number of children = x + y = 1 + 3/2 = 5/2

Therefore, there are a total of 5/2 children in this family.

Please note that the given information does not provide a whole number of children in the family, which is unusual. It is possible that there is missing or incomplete information in the question.

Let me know if there's anything else I can help you with!