Question

Во дворе у Дамира кролики и куры.Испугавшись вбежавшей во двор собаки все они выскочили со двора.Дамир,загоняя их,затратил на каждого кролика по 2 мин,на каждую курицу-по 3 мин.На это ушло всего 0,5 часов.Сколько кроликов и сколько куриц у Дамира?

Answer 1

0,5 ч = 30 мин
Пусть х - кролики, тогда у - куры
2х+3у=30
2х=30-3у
х=(30-3у)/2
х=15-1,5у  - это кролики

дальше подставляем
если 1 курица, то
х=15-1,5*1
х=15-1,5 - невозможно (половины животного не бывает), 
значит по условию понимаем, что кур только чётное число
пусть кур 2, тогда
х= 15 - 1,5 * 2
х= 15-3
х=12 - кролики

пусть кур 4, тогда
х=15-1,5*4
х=15-6
х=9 - кроликов

пусть кур 6, тогда
х=15-1,5*6
х=15-9
х=6 - кроликов

пусть кур 8, тогда
х=15-1,5*8
х=15-12
х=3

пусть кур 10, тогда
х=15-1,5*10  - невозможно

следовательно:  решений задачи может быть 4 
2 куры, 12 кроликов
4 куры, 9 кроликов
6 кур, 6 кроликов
8 кур, 3 кролика

ну, как-то так))

Answer 2

Problem Analysis

In this problem, we are given that there are rabbits and chickens in Damir's yard. When a dog enters the yard, all the animals run out of the yard. Damir spends 2 minutes for each rabbit and 3 minutes for each chicken to bring them back into the yard. The total time spent is 0.5 hours. We need to determine the number of rabbits and chickens Damir has.

Solution

Let's assume that Damir has x rabbits and y chickens.

According to the given information, Damir spends 2 minutes for each rabbit and 3 minutes for each chicken to bring them back into the yard. The total time spent is 0.5 hours, which is equal to 30 minutes.

Based on this information, we can set up the following equation:

2x + 3y = 30

Now, we need to solve this equation to find the values of x and y.

Solving the Equation

To solve the equation, we can use various methods such as substitution or elimination. Let's use the substitution method.

From the equation 2x + 3y = 30, we can isolate one variable and express it in terms of the other variable. Let's isolate x:

2x = 30 - 3y

x = (30 - 3y) / 2

Now, we can substitute this expression for x into the equation 2x + 3y = 30:

2((30 - 3y) / 2) + 3y = 30

Simplifying the equation:

30 - 3y + 3y = 30

30 = 30

The equation simplifies to 30 = 30, which is always true. This means that the equation is satisfied for any value of y.

Since the equation is satisfied for any value of y, there are infinitely many solutions to this problem. Damir can have any number of rabbits and chickens as long as the total time spent bringing them back into the yard is 0.5 hours (30 minutes).

Therefore, we cannot determine the exact number of rabbits and chickens Damir has based on the given information.

Conclusion

Based on the given information, we cannot determine the exact number of rabbits and chickens Damir has in his yard. The equation 2x + 3y = 30 has infinitely many solutions, and Damir can have any number of rabbits and chickens as long as the total time spent bringing them back into the yard is 0.5 hours (30 minutes).