13.163. When harvesting, 210 centners of wheat were collected from each of two plots. The area of the first plot is 0.5 hectares less than the area of the second plot. How many centners of wheat were collected per hectare on each plot if the wheat yield on the first plot was 1 centner per hectare more than on the second?
Solution.

Let $x$ ha be the area of the first plot, $(x+0.5)$ ha be the area of the second. From 1 ha on the first plot, $\frac{210}{x}$ centners of wheat were collected, and from the second plot, $\frac{210}{x+0.5}$ centners. According to the condition, $\frac{210}{x}-\frac{210}{x+0.5}=1$, from which $x=10$ ha. From 1 ha on the first plot, $\frac{210}{10}=21$ centners of wheat were collected, and from the second - 20 centners.

Answer: 21 and 20 centners.