Question

За 15 открыток без марок нужно заплатить 10 рублей 50 копеек.Открытка в 2 раза дешевле марки.Какова стоимость 8 открыток с марками.

Answer 1

10 руб 50 копеек =1050копеек
1050/15=70 копеек 1 открытка
70*2=1руб 40 копеек 1 марка
(70*8=560копеек +140*8=1120копеек)=1680копеек=16 руб 80 коп

Answer 2

1)1050:15=70коп стоит одна открытка
2)70•2=1,40 коп стоит марка
3)140+70=2,10 коп стоит марка и открытка вместе
4)210•8=16,80 коп стоят 8 открыток с маркой

Answer 3

Calculation of Postcard Costs

To calculate the cost of 8 postcards with stamps, we can use the given information that 15 postcards without stamps cost 10 rubles and 50 kopeks, and that a postcard is two times cheaper than a stamp.

Given: - Cost of 15 postcards without stamps = 10 rubles 50 kopeks - Postcard is 2 times cheaper than a stamp

Calculation Steps

1. Cost of 1 postcard without a stamp: - Let's first calculate the cost of 1 postcard without a stamp. - We can use the given information that 15 postcards without stamps cost 10 rubles 50 kopeks.

- Cost of 1 postcard without a stamp = (Cost of 15 postcards without stamps) / 15 - Cost of 1 postcard without a stamp = 10 rubles 50 kopeks / 15

- Cost of 1 postcard without a stamp = 10 rubles 50 kopeks / 15 - Cost of 1 postcard without a stamp = 0 rubles 70 kopeks

Result: The cost of 1 postcard without a stamp is 70 kopeks.

2. Cost of 1 stamp: - Since a postcard is 2 times cheaper than a stamp, we can calculate the cost of 1 stamp.

- Cost of 1 stamp = 2 * (Cost of 1 postcard without a stamp) - Cost of 1 stamp = 2 * 70 kopeks

- Cost of 1 stamp = 1 ruble 40 kopeks

Result: The cost of 1 stamp is 1 ruble 40 kopeks.

3. Cost of 8 postcards with stamps: - Now, we can calculate the cost of 8 postcards with stamps.

- Cost of 8 postcards with stamps = (Cost of 8 postcards) + (Cost of 8 stamps) - Cost of 8 postcards with stamps = (8 * Cost of 1 postcard without a stamp) + (8 * Cost of 1 stamp)

- Cost of 8 postcards with stamps = (8 * 70 kopeks) + (8 * 1 ruble 40 kopeks) - Cost of 8 postcards with stamps = 5 rubles 60 kopeks + 11 rubles 20 kopeks

- Cost of 8 postcards with stamps = 16 rubles 80 kopeks

Result: The cost of 8 postcards with stamps is 16 rubles 80 kopeks.

Conclusion

The cost of 8 postcards with stamps is 16 rubles 80 kopeks.