Question

ДАЮ 100 БАЛЛОВ! ДАТЬ ПОЛНОЕ РЕШЕНИЕ С ОБЪЯСНЕНИЯМИ! РЕШЕНИЕ ОБЯЗАТЕЛЬНО! ПРОСТО ОТВЕТЫ НЕ ПРИНИМАЮТСЯ! Чашка кофе с молоком стоит 80 рублей, такая же чашка кофе без молока — 95 рублей, а такая же чашка молока — 20 рублей. Сколько молока в чашке кофе с молоком? Ответ дайте в процентах.

Answer 1

Х мл в кружке
95/х стоит мл кофе
20/х стоит мл молока
пусть налили а мл кофе и в мл молока
тогда
(95/х)*а+(20/х)в=80
а=х-в
(95/х)(х-в)+(20/х)в=80
95(х-в)+20в=80х
95х-95в+20в=80х
75в=15х
75/15в=х
5в=х
в=1/5х
то есть
молока одна пятая часть
а  кофе 4/5
проверка
1/5*20+4/5*95=4+76=80
(1/5)*100%=0,2*100%=20%
4/5*100%=0,8*100%=80%

Answer 2

Problem Analysis

To find out how much milk is in a cup of coffee with milk, we need to compare the prices of different types of coffee. We are given the prices of a cup of coffee with milk, a cup of coffee without milk, and a cup of milk. By comparing the prices, we can determine the percentage of milk in the cup of coffee with milk.

Solution

Let's assume that the cup of coffee with milk contains x% milk. We can set up the following equation based on the given information:

80 rubles (price of coffee with milk) = x% (milk content) * 20 rubles (price of milk) + (100 - x)% (coffee content) * 95 rubles (price of coffee without milk)

Simplifying the equation, we get:

80 = 0.2x + 0.95(100 - x)

Now, let's solve this equation to find the value of x, which represents the percentage of milk in the cup of coffee with milk.

Calculation

To solve the equation, we can follow these steps:

1. Distribute 0.95 to both terms inside the parentheses: 80 = 0.2x + 95 - 0.95x

2. Combine like terms: 80 = 95 - 0.75x

3. Move the constant term to the other side of the equation: 0.75x = 95 - 80

4. Simplify: 0.75x = 15

5. Divide both sides of the equation by 0.75 to isolate x: x = 15 / 0.75

6. Calculate the value of x: x = 20

Therefore, the cup of coffee with milk contains 20% milk.

Answer

The cup of coffee with milk contains 20% milk.