Question

Решить задачу: Виноград содержит 91% влаги, а изюм - 7%. Сколько килограммов винограда требуется для получения 21 кг изюма? Сколько килограммов изюма получится из 10 кг винограда?

Answer 1

Нехай х - вага виногаду,  робимо через відношення, 
1) 7           91
    ---     -  -----
    21          х
х=91*21/7
х=273 кг винограду
2) 273        21
   ------   --  -----
    10           х 
х=10*21/273
х=210/273
х=1,3 кг

Answer 2

Problem Analysis

To solve this problem, we need to determine the amount of grapes required to obtain a certain amount of raisins and vice versa. We are given that grapes contain 91% water and raisins contain 7% water. We need to find the weight of grapes required to obtain 21 kg of raisins and the weight of raisins obtained from 10 kg of grapes.

Solution

Let's start by calculating the weight of grapes required to obtain 21 kg of raisins.

Let's assume the weight of grapes required is x kg.

The weight of water in x kg of grapes = 91% of x kg = 0.91x kg

The weight of raisins obtained from x kg of grapes = x kg - weight of water = x kg - 0.91x kg = 0.09x kg

According to the problem, the weight of raisins obtained is 21 kg. So we can set up the following equation:

0.09x kg = 21 kg

Solving this equation, we can find the value of x:

x = 21 kg / 0.09 = 233.33 kg

Therefore, to obtain 21 kg of raisins, we need approximately 233.33 kg of grapes.

Now let's calculate the weight of raisins obtained from 10 kg of grapes.

Let's assume the weight of raisins obtained is y kg.

The weight of water in 10 kg of grapes = 91% of 10 kg = 0.91 * 10 kg = 9.1 kg

The weight of raisins obtained from 10 kg of grapes = 10 kg - weight of water = 10 kg - 9.1 kg = 0.9 kg

Therefore, from 10 kg of grapes, we can obtain approximately 0.9 kg of raisins.

Answer

To obtain 21 kg of raisins, approximately 233.33 kg of grapes are required. From 10 kg of grapes, approximately 0.9 kg of raisins can be obtained.

Please let me know if you need any further clarification.