What formula is used to calculate the water needed for a part tank?

The correct choice involves calculating the amount of water needed for a part tank by multiplying the area left to spray by the sprayer output, expressed in liters per hectare. This formula allows the applicator to determine precisely how much solution is required based on the amount of area that remains untreated and the efficiency of the sprayer, which is represented as the output in liters per hectare.

When applying pesticides or any agricultural inputs, knowing how much solution is required for the specific area is crucial for effective and efficient application. This method ensures that the applicator can properly mix the chemicals in the appropriate amounts, preventing under or over-application, which could lead to inadequate pest control or environmental harm.

The other choices suggest different methods of calculating pesticide requirements but do not provide the correct approach for determining the necessary water for a part tank. Specifically, alternatives like dividing area sprayed or adjusting application rates without directly correlating them with sprayer output miss the essential principle of directly relating area left to spray and the sprayer's capability.