28. Determine the length of the path over which the amount of grain in the seeder's box will decrease by $14 \%$, if the box has a working width of 4 m, it was filled with 250 kg of grain, and the sowing rate is 175 kg per 1 ha.
28. If the amount of grain in the seeder's box decreases by $14 \%$, then 35 kg of grain will be sown $(250 \cdot 0.14=35)$. This constitutes $\frac{35}{175}=\frac{1}{5}$ of the sowing norm per 1 ha, which means that an area of $\frac{1}{5}$ ha, or $2000 \mathrm{~m}^{2}(10000: 5=2000)$, has been sown. Knowing the width of the cut, we can find the length of the path $2000: 4=500$ (m).