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'.

Input: Consider Input: Problem: a and b together do a work in 20 days . b and c together in 15 days and c and a in 12 days . so a , b and c together finish same work in how many days ?
Options: a ) 12 , b ) 15 , c ) 8 , d ) 10 , e ) 11

Output: d

Input: Consider Input: Problem: if 36 men can do a piece of work in 5 hours , in how many hours will 15 men do it ?
Options: a ) 12 , b ) 38 , c ) 60 , d ) 88 , e ) 72

Output: a

Input: Consider Input: Problem: a boat running up stram takes 4 hours to cover a certain distance , while it takes 8 hours to cover the same distance running down stream . what is the ratio between the speed of the boat and the speed of water current respectively ?
Options: a ) 2 : 3 , b ) 5 : 6 , c ) 4 : 5 , d ) 3 : 1 , e ) 8 : 1
Output: d