TASK DEFINITION: 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'.
PROBLEM: Problem: a , b , k start from the same place and travel in the same direction at speeds of 30 km / hr , 40 km / hr , 80 km / hr respectively . b starts two hours after a . if b and k overtake a at the same instant , how many hours after a did k start ? 
Options: a ) 2 , b ) 3 , c ) 4 , d ) 5 , e ) 6

SOLUTION: d

PROBLEM: Problem: mary can do a piece of work in 28 days . rosy is 40 % more efficient than mary . the number of days taken by rosy to do the same piece of work is ? 
Options: a ) 22 , b ) 24 , c ) 20 , d ) 25 , e ) 27

SOLUTION: c

PROBLEM: Problem: a can do a piece of work in 6 days . b can do it in 6 days . with the assistance of c they completed the work in 2 days . find in how many days can c alone do it ? 
Options: a ) 8 days , b ) 2 days , c ) 6 days , d ) 7 days , e ) 4 days

SOLUTION:
c