Question

Реши задачу в 1 действие.3 конверта на 12 руб. дешевле 5 таких же конвертов. На сколько стоимость 11 таких конвертов больше стоимости 9 конвертов если цена конверта постоянна

Answer 1

Problem Analysis

We are given that the price of 3 envelopes is 12 rubles cheaper than the price of 5 envelopes. We need to determine how much the cost of 11 envelopes is greater than the cost of 9 envelopes, assuming the price per envelope remains constant.

Solution

Let's assume the price of one envelope is x rubles.

According to the given information, the price of 3 envelopes is 12 rubles cheaper than the price of 5 envelopes. Mathematically, we can express this as:

5x - 3x = 12

Simplifying the equation, we get:

2x = 12

Dividing both sides by 2, we find:

x = 6

Therefore, the price of one envelope is 6 rubles.

Now, we need to determine how much the cost of 11 envelopes is greater than the cost of 9 envelopes.

The cost of 11 envelopes can be calculated as:

11 * x = 11 * 6 = 66 rubles

Similarly, the cost of 9 envelopes can be calculated as:

9 * x = 9 * 6 = 54 rubles

Therefore, the cost of 11 envelopes is 66 rubles, which is 12 rubles greater than the cost of 9 envelopes.

Answer

The cost of 11 envelopes is 12 rubles greater than the cost of 9 envelopes, assuming the price per envelope remains constant.