Question

Одна открытка,2 одиннаковых конверта и 3 одинаковые марки стоит 38 руб. три такие открытки ,2 таких конверта и 1 такая же марка стоят 22 р. сколько стоит набор из открытки,конверта и марки?

Answer 1

Обозначим - О = открытка, К =  конверт, М = марка. Тогда условие задачи можно записать кратко
ДАНО
1)  О    +2*К+  3*М = 38 руб
2) 3*О +2*К+      М=22  руб.
НАЙТИ
О+К+М = ? - стоимость комплекта.
ДУМАЕМ - просто смотрим на эти уравнения и видим, что надо сложить и разделить.
РЕШЕНИЕ
Суммируем 1) и 2) и получаем
3)  4*(О+К+М) = 38+22= 60 - 4 комплекта - нам нужен всего один - делим
4) О+К+М = 60/4= 15 руб.
ОТВЕТ: Стоимость комплекта 15 рублей. 

Answer 2

Problem Analysis

We are given the following information: - One greeting card, two identical envelopes, and three identical stamps cost 38 rubles. - Three such greeting cards, two such envelopes, and one such stamp cost 22 rubles.

We need to find the cost of a set consisting of one greeting card, one envelope, and one stamp.

Solution

Let's assume the cost of one greeting card is x rubles, the cost of one envelope is y rubles, and the cost of one stamp is z rubles.

From the given information, we can form the following equations:

Equation 1: x + 2y + 3z = 38 (since one greeting card, two envelopes, and three stamps cost 38 rubles) Equation 2: 3x + 2y + z = 22 (since three greeting cards, two envelopes, and one stamp cost 22 rubles)

To solve these equations, we can use the method of substitution or elimination. Let's use the method of elimination.

Multiplying Equation 1 by 3 and Equation 2 by 2, we get:

Equation 3: 3x + 6y + 9z = 114 Equation 4: 6x + 4y + 2z = 44

Subtracting Equation 4 from Equation 3, we get:

3x + 6y + 9z - (6x + 4y + 2z) = 114 - 44 -3x + 2y + 7z = 70 (Equation 5)

Now we have two equations: Equation 2: 3x + 2y + z = 22 Equation 5: -3x + 2y + 7z = 70

Adding Equation 2 and Equation 5, we get:

(3x + 2y + z) + (-3x + 2y + 7z) = 22 + 70 9z = 92 z = 92/9

Substituting the value of z back into Equation 2, we can solve for x:

3x + 2y + (92/9) = 22 27x + 18y + 92 = 198 27x + 18y = 198 - 92 27x + 18y = 106 9x + 6y = 35 (Equation 6)

Now we have two equations: Equation 6: 9x + 6y = 35 Equation 5: -3x + 2y + 7z = 70

Multiplying Equation 6 by 2 and Equation 5 by 3, we get:

18x + 12y = 70 -9x + 6y + 21z = 210

Adding these two equations, we get:

18x + 12y + (-9x + 6y + 21z) = 70 + 210 9x + 18y + 21z = 280 9(x + 2y + 3z) = 280 9(38) = 280 342 = 280

This is not a valid equation, which means there is no solution that satisfies all the given conditions.

Therefore, we cannot determine the cost of a set consisting of one greeting card, one envelope, and one stamp based on the given information.

Please let me know if there is anything else I can help you with.