Question

у Сергея было 90 коп ,а у Татьяны 63 коп. когда Сергей купил 8 марок ,а Таня 5 то денег у них стало поровну.сколько стоит одна марка

Answer 1

Пусть 1 марка стоит х коп.
тогда 90-8*х=63-5*х
90-63=8*х-5*х
27=3*х
х=9
одна марка стоит 9 коп.

Answer 2

Calculation of the Cost of One Stamp

To calculate the cost of one stamp, we can use the given information about the amount of money Sergey and Tatyana had before and after buying stamps.

According to the information provided, Sergey had 90 kopeks and Tatyana had 63 kopeks. After Sergey bought 8 stamps and Tatyana bought 5 stamps, they had an equal amount of money left.

Let's calculate the total amount of money they spent on stamps:

- Sergey spent 8 stamps * X kopeks per stamp = 8X kopeks - Tatyana spent 5 stamps * X kopeks per stamp = 5X kopeks

After buying the stamps, Sergey and Tatyana had an equal amount of money left, so we can set up the following equation:

90 kopeks - 8X kopeks = 63 kopeks - 5X kopeks

Let's solve this equation to find the value of X, which represents the cost of one stamp.

90 kopeks - 8X kopeks = 63 kopeks - 5X kopeks

90 kopeks - 63 kopeks = 8X kopeks - 5X kopeks

27 kopeks = 3X kopeks

Dividing both sides of the equation by 3, we get:

9 kopeks = X kopeks

Therefore, the cost of one stamp is 9 kopeks.

Please note that the search results did not provide direct information about the cost of one stamp. The calculation above is based on the given information and the assumption that the cost of each stamp is the same.