Question

Мама купила 5 тетрадей а бабушка 7 тетрадей по одной и той же цене. Сколько стоит одна тетрадь если бабушка заплатила за свою покупку на 1 руб. 80 коп. больше чем мама? Сколько денег израсходовала мама на покупку тетрадей? Сколько денег израсходовала бабушка на покупку тетрадей?

Answer 1

7-5=2 (т.) 1руб. 80коп.=180коп.
180:2=90 (руб.)-1 тетрадь

90×5=450 (руб.)-мама
90×7=630 (руб.)-бабушка

Answer 2

Problem Analysis

We are given that the mother bought 5 notebooks and the grandmother bought 7 notebooks, all at the same price. The grandmother paid 1 ruble and 80 kopeks more than the mother. We need to determine the price of one notebook and calculate how much money the mother and grandmother spent on their purchases.

Solution

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

According to the given information, the grandmother paid 1 ruble and 80 kopeks more than the mother. This can be expressed as:

7x = 5x + 1 ruble 80 kopeks

To solve this equation, we need to convert the kopeks to rubles. Since 100 kopeks make 1 ruble, we can rewrite the equation as:

7x = 5x + 1.8 rubles

Now, let's solve for x:

7x - 5x = 1.8 rubles

2x = 1.8 rubles

x = 0.9 rubles

Therefore, the price of one notebook is 0.9 rubles.

To calculate how much money the mother spent on the notebooks, we multiply the price of one notebook by the number of notebooks she bought:

Mother's expenditure = 5 notebooks * 0.9 rubles/notebook = 4.5 rubles

To calculate how much money the grandmother spent on the notebooks, we multiply the price of one notebook by the number of notebooks she bought:

Grandmother's expenditure = 7 notebooks * 0.9 rubles/notebook = 6.3 rubles

Answer

- The price of one notebook is 0.9 rubles. - The mother spent 4.5 rubles on the notebooks. - The grandmother spent 6.3 rubles on the notebooks.

Please let me know if you need any further assistance.