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: two buses each 3125 m long are running in opposite directions on parallel roads . their speeds are 40 km / hr and 35 km / hr respectively . find the time taken by the slower bus to pass the driver of the faster one ? 
Options: a ) 50 sec , b ) 66 sec , c ) 48 sec , d ) 55 sec , e ) 45 sec

Output: a


Input: Consider Input: Problem: if the population of a certain country increases at the rate of one person every 30 seconds , by how many persons does the population increase in 10 minutes ? 
Options: a ) 20 , b ) 30 , c ) 15 , d ) 10 , e ) 80


Output: a