Question

За 15 открыток, 10 конвертов и блокнот заплатили 36 руб. Конверт в 4 раза дешевле блокнота и на 50 коп. дороже открытки.Сколько стоит открытка-конверт блокнот.Помогите пожалуйста ❤️

Answer 1

Открытка 1р, конверт 1р50к, блокнот 6р

Answer 2

Calculation of Prices

To solve this problem, let's assign variables to the prices of the items mentioned: - Let's call the price of an open card "x" rubles. - The price of a envelope will be "y" rubles. - The price of a notebook will be "z" rubles.

Based on the given information, we can create the following equations:

1. From the statement "For 15 open cards, 10 envelopes, and a notebook, they paid 36 rubles": - Equation 1: 15x + 10y + z = 36

2.#### Calculation of Prices

To solve this problem, let's assign variables to the prices of the items mentioned:

Let: - Price of an open card = x rubles - Price of an envelope = y rubles - Price of a notebook = z rubles

According to the given information, we have the following equations:

1. 15 open cards + 10 envelopes + 1 notebook = 36 rubles - 15x + 10y + z = 36 2. An envelope is 4 times cheaper than a notebook - y = (1/4)z

3. An envelope is 50 kopeks more expensive than an open card - y = x + 0.5

Now, let's solve these equations to find the prices of the open card, envelope, and notebook.

Solving the Equations

Substituting equation 2 into equation 3, we get:

(1/4)z = x + 0.5

Simplifying equation 2, we have:

z = 4y

Substituting this into the previous equation, we get:

(1/4)(4y) = x + 0.5

Simplifying further:

y = x + 0.5

Now, we can substitute these equations into equation 1:

15x + 10(x + 0.5) + 4(x + 0.5) = 36

Simplifying and solving for x:

15x + 10x + 5 + 4x + 2 = 36 29x + 7 = 36 29x = 29 x = 1

Now that we have the value of x, we can find the values of y and z:

y = x + 0.5 = 1 + 0.5 = 1.5 z = 4y = 4 * 1.5 = 6

Calculation of Prices

Based on the calculations, we have found the following prices:

- The price of an open card is 1 ruble. - The price of an envelope is 1.5 rubles. - The price of a notebook is 6 rubles.

Therefore, the cost of an open card-envelope-notebook set is 1 + 1.5 + 6 = 8.5 rubles.

Please note that the calculations are based on the given information and assumptions made.