3.1 The tractor driver plowed three plots of land. The area of the first is $\frac{2}{5}$ of the total area of all three plots, and the area of the second is to the area of the third as $\frac{3}{2}: \frac{4}{3}$. How many hectares were there in all three plots if the third plot was 16 hectares smaller than the first?
3.1 The areas of the plots are equal to $x, y, x-16$ (ha). According to the condition, $x=\frac{2}{5}(x+y+x-16)$ and $y:(x-16)=\frac{3}{2}: \frac{4}{3}$, from which $y=\frac{9}{8}(x-16)$. Further, we have $x=\frac{2}{5}\left(2 x-16+\frac{9}{8} x-18\right)$, or $x=\frac{2}{5}\left(\frac{25 x}{8}-34\right)$, from which $x=\frac{272}{5}$. Now we find $y=\frac{9}{8}\left(\frac{272}{5}-16\right)=\frac{216}{5}$. The total area is $\frac{544}{5}+\frac{216}{5}-16=136$ (ha).

Omeem: 136 ha.