The main drive wheel diameter of a 7$\times$20 cm seed-drill is 140 cm. During calibration, the total weight of grain collected after 20 revolution of drive wheel is 0.154 kg. Calculate the seed rate in kg per hectare for the seed-drill neglecting wheel slippage.
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To simplify seed-drill calculations, use the consolidated formula:
\[ \text{Seed Rate (kg/ha)} = \frac{10,000 \times w}{n \times \pi \times D \times W} \]
This helps avoid rounding errors at intermediate steps.