16.3. An old problem. The master hired a worker for a year and promised to give him 12 rubles and a coat. But after 7 months, the worker wanted to leave. Upon settlement, he received the coat and 5 rubles. How much did the coat cost

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12
16.3. Let the cost of the kaftan be $x$ rubles. Monthly, the worker's share was $(1+x: 12)$ rubles. Therefore, over 7 months, he should have received $(7+7 x: 12)$ rubles, but he received $(5+x)$ rubles. We have the equation: $7+7 x: 12=5+x$. From this, $x=4.8$. Answer: The kaftan cost 4 rubles and 80 kopecks.