Question

Помогите,пожалуйста!Отправляясь,за покупками,я имел в кошельке около 15 рублей,отдельными рублями и 20-копеечными монетами.Возвратившись,я принес столько отдельных рублей,сколько у меня было первоначально 20-копеечных монет,и столько 20-копеечных монет,сколько я имел раньше отдельных рублей.Всего же уцелела у меня в кошельке треть той суммы,с которой я отправился за покупками.Сколько стоили покупки?

Answer 1

15:3= 5 рублей  - треть от первоначальной суммы
15-5= 10 рублей - стоимость покупок.
Нигде в задаче на спрашивается сколько это в рублях и монетах перечень монет и рублей дается чтобы сбить с толку.

Answer 2

Problem Analysis

To solve this problem, we need to determine the cost of the purchases made based on the information provided. Let's break down the given information:

- Initially, the person had 15 rubles in their wallet, consisting of separate ruble coins and 20-kopeck coins. - When they returned, they brought back the same number of separate ruble coins as the number of 20-kopeck coins they had initially. - They also brought back the same number of 20-kopeck coins as the number of separate ruble coins they had initially. - In the end, they had one-third of the original amount left in their wallet.

We need to find the cost of the purchases made.

Solution

Let's assume the number of separate ruble coins initially was x, and the number of 20-kopeck coins initially was y.

1. Initially, the person had 15 rubles, which can be represented as x rubles + 0.2y rubles. 2. When they returned, they brought back y separate ruble coins and x 20-kopeck coins. 3. The total amount they brought back can be represented as y rubles + 0.2x rubles. 4. In the end, they had one-third of the original amount left, which is (15 rubles)/3 = 5 rubles.

Now, we can set up the following equations based on the information given:

Equation 1: x rubles + 0.2y rubles = 15 rubles Equation 2: y rubles + 0.2x rubles = 5 rubles

We can solve these equations to find the values of x and y, which will give us the cost of the purchases made.

Let's solve the equations:

Equation 1: x + 0.2y = 15 (multiply by 10 to eliminate decimals) Equation 2: y + 0.2x = 5 (multiply by 10 to eliminate decimals)

Multiply Equation 1 by 2 and Equation 2 by -1 to eliminate 0.2x:

Equation 3: 2x + 0.4y = 30 Equation 4: -x - 0.2y = -5

Add Equation 3 and Equation 4 to eliminate y:

Equation 5: x = 25

Substitute the value of x into Equation 1 to find y:

25 + 0.2y = 15 0.2y = -10 y = -50

Since the number of coins cannot be negative, we can conclude that there is no valid solution to this problem. It is not possible to determine the cost of the purchases made based on the given information.

Conclusion

Based on the given information, it is not possible to determine the cost of the purchases made. The problem does not provide enough information to calculate the cost accurately.