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 train running at the speed of 120 km / hr crosses a pole in 18 seconds . what is the length of the train ?
Options: a ) 560 , b ) 570 , c ) 580 , d ) 590 , e ) 600
[EX A]: e

[EX Q]: Problem: 20 beavers , working together in a constant pace , can build a dam in 3 hours . how many v hours will it take 12 beavers that work at the same pace , to build the same dam ?
Options: a ) 2 . , b ) v = 4 . , c ) v = 5 . , d ) v = 6 . , e ) 8 .
[EX A]:
c