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: two trains are moving in opposite directions at 60 km / hr and 90 km / hr . their lengths are 1.25 km and 1.00 km respectively . the time taken by the slower train to cross the faster train in seconds is ? 
Options: a ) 48 , b ) 9 , c ) 7 , d ) 67 , e ) 54
[EX A]: e

[EX Q]: Problem: 13 buckets of water fill a tank when the capacity of each bucket is 51 litres . how many buckets will be needed to fill the same tank , if the capacity of each bucket is 17 litres ? 
Options: a ) 39 , b ) 28 , c ) 23 , d ) 12 , e ) 24
[EX A]: a

[EX Q]: Problem: a can do a piece of work in 15 days and b can do it in 15 days and c can do it 20 days . they started the work together and a leaves after 2 days and b leaves after 4 days from the beginning . how long will work lost ? 
Options: a ) 15 , b ) 10 , c ) 12 , d ) 11 , e ) 13
[EX A]:
c