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'.

[Q]: Problem: two pipes a and b can separately fill a tank in 12 and 20 minutes respectively . a third pipe c can drain off 45 liters of water per minute . if all the pipes are opened , the tank can be filled in 15 minutes . what is the capacity of the tank ? 
Options: a ) 542 , b ) 540 , c ) 675 , d ) 829 , e ) 279
[A]: c


[Q]: Problem: a worker earns $ 20 on the first day and spends $ 15 on the second day . the worker earns $ 20 on the third day and spends $ 15 on the fourth day . if this pattern continues , on which day will the worker first reach a net total of $ 90 ? 
Options: a ) 28 , b ) 29 , c ) 31 , d ) 34 , e ) 36
[A]: b


[Q]: Problem: a train passes a platform in 40 seconds . the same train passes a man standing on the platform in 20 seconds . if the speed of the train is 54 km / hr , the length of the platform is 
Options: a ) 280 meter , b ) 240 meter , c ) 200 meter , d ) 300 meter , e ) none of these
[A]:
d