Answer:
Step-by-step explanation:
We can treat this as a units conversion problem. Each multiplier is a fraction that has the same value in the numerator as the denominator, but expresses that value with different units. We choose to cancel units we don't want, and replace them with units we do want. Ultimately, we're evaluating the expression ...
time = quantity/rate
(4 mi²) × (640 ac/mi²) × (5 min)/(2.5 ac) × (1 h)/(60 min)
= (4·640·5)/(2.5·60) h = 85 1/3 h
It will take about 85 hours to plant the farm.
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At 8 hours per day, that is (85 1/3)/(8) = 10 2/3 days.
It will take about 11 days to plant the farm.
