[ Inequalities Problems. Case Analysis]

9 kg of candies cost less than 10 rubles, and 10 kg of the same candies cost more than 11 rubles. How much does 1 kg of these candies cost?
The first condition is equivalent to the statement that 1 kg of candies costs less than $10 / 9$ rubles $= 1$ ruble $11_{1}^{1} / 9$ kopecks. Similarly, the second condition is equivalent to the statement that 1 kg of candies costs more than ${ }^{11} / 10$ rubles = 1 ruble 10 kopecks. Therefore, the answer to the problem is any amount greater than 1 ruble 10 kopecks and less than 1 ruble $11^{1 / 9}$ kopecks. Therefore, the answer is unambiguous: 1 ruble 11 kopecks.

## Answer

1 ruble 11 kopecks.