Task: Question Answering
Input (English): Problem: the consumption of diesel per hour of a bus varies directly as square of its speed . when the bus is travelling at 60 kmph its consumption is 1 litre per hour . if each litre costs $ 30 and other expenses per hous is $ 20 , then what would be the minimum expenditure required to cover a distance of 600 km ? 
Options: a ) 500 , b ) 450 , c ) 600 , d ) 650 , e ) 750
Output (English): a