14.2. For 9 identical books, more than 11 rubles were paid, and for 13 such books, less than 16 rubles were paid. How much does one book cost?

$$
(6-7 \text { grade) }
$$
14.2. According to the condition of the problem, the cost of one book in kopecks is within the following limits:

$$
\frac{1100}{9}<x<\frac{1600}{13} \text { or } \quad 122 \quad \frac{2}{9}<x<123 \frac{1}{13}
$$

from which we conclude that one book costs 123 kopecks = 1 r. 23 kopecks.