In this task, you need to answer the given multiple-choice question on the physics. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

[EX Q]: Problem: to fill a tank , 20 buckets of water is required . how many buckets of water will be required to fill the same tank if the capacity of the bucket is reduced to one - fifth of its present ? 
Options: a ) 100 , b ) 200 , c ) 300 , d ) 400 , e ) 500
[EX A]: a

[EX Q]: Problem: a cube of side two meter length is cut into small cubes of side 10 cm each . how many such small cubes can be obtained ? 
Options: a ) 2878 , b ) 2778 , c ) 1000 , d ) 8000 , e ) 8900
[EX A]: d

[EX Q]: Problem: darcy lives 1.5 miles from work . she can walk to work at a constant rate of 3 miles per hour , or she can ride the train to work at a constant rate of 20 miles per hour . if she rides the train , there is an additional x minutes spent walking to the nearest train station , waiting for the train , and walking from the final train station to her work . if it takes darcy a total of 2 more minutes to commute to work by walking than it takes her to commute to work by riding the train , what is the value of x ? 
Options: a ) 10.5 , b ) 15 , c ) 25.5 , d ) 30 , e ) 23.5
[EX A]:
e