GATE 2024 AG – Question 39
A 4.2 m combine travels3.5 km/hour at 75% field efficiency and harvests300 ha/year. Variable cost scales linearly with actual operating hours. What extra annual area would reduce hourly operating cost15%?
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Correct answer: (A) 52.94
Explanation
The official answer assumes the hourly cost component being reduced is fixed annual cost spread over more hours. Since area is proportional to hours,$300/A_{new}=.85$,so $A_{new}=352.9412$ ha and extra area is **52.94 ha, A**. For full hourly cost $F/H+v$,a 15% reduction cannot be uniquely calculated without the fixed/variable cost split. A constant variable cost per hour does not decrease as annual use increases; this missing-cost assumption is explicit.