Question

Три лошади съедают все сено в сарае за 2 дня. Первая лошадь съедает сама всё это сено за 5 дней, а вторая за 20 дней. За сколько дней съедает все сено в сарае третья лошадь самостоятельно? А) 4 дня B) 2 дня C) 10 дней D) 12 днейПожалуйста ответ с объяснением ​

Answer 1

Ответ:

Ответ: за 4 дня

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1. У нас есть 3 лошади.

2. Дано:

1 лошадь — съедает сено за 5 дней

2 лошадь — за 20 дней

3 лошадь — ?

3. Решение:

1) 20 : 5 = 4

4. Ответ:

За 4 дня съедает сено 3-тья лошадь

Answer 2

Problem Analysis

We are given that three horses eat all the hay in a barn in 2 days. The first horse eats all the hay in 5 days, and the second horse eats all the hay in 20 days. We need to determine how many days it will take for the third horse to eat all the hay by itself.

Solution

Let's assume that the amount of hay in the barn is represented by the variable "H". Since all three horses eat all the hay in 2 days, we can set up the following equation:

Amount of hay eaten by the first horse in 1 day + Amount of hay eaten by the second horse in 1 day + Amount of hay eaten by the third horse in 1 day = Total amount of hay in the barn

Let's calculate the amount of hay eaten by each horse in 1 day:

- The first horse eats all the hay in 5 days, so it eats 1/5 of the hay in 1 day. - The second horse eats all the hay in 20 days, so it eats 1/20 of the hay in 1 day. - Let's represent the amount of hay eaten by the third horse in 1 day as "x".

Now we can set up the equation:

1/5 + 1/20 + x = 1

Simplifying the equation:

4/20 + 1/20 + x = 1

5/20 + x = 1

x = 1 - 5/20

x = 20/20 - 5/20

x = 15/20

x = 3/4

Therefore, the third horse eats 3/4 of the hay in the barn in 1 day.

To find out how many days it will take for the third horse to eat all the hay by itself, we can set up the following equation:

Amount of hay eaten by the third horse in 1 day * Number of days = Total amount of hay in the barn

Let's solve for the number of days:

(3/4) * Number of days = 1

Number of days = 1 / (3/4)

Number of days = 4/3

Number of days = 1 1/3

Therefore, it will take the third horse 1 1/3 days to eat all the hay in the barn by itself.

Answer

The third horse will take 1 1/3 days to eat all the hay in the barn by itself.