24. The moisture content of freshly cut grass is $70 \%$, and the moisture content of hay is $16 \%$. How much grass needs to be cut to obtain 1 ton of hay?
24. In 1 t of dry hay, there will be $840 \mathrm{kr}(100 \%-16 \%=84 \%, 1000 \cdot 0,84=840)$. In fresh-cut grass, the dry mass constitutes $30 \%(100 \%-70 \%=30 \%)$. Therefore, the amount of grass needed is $840: 0,3=2800$ (kg). Thus, to obtain 1 t of hay, 2.8 t of grass must be cut.