Important Facts: 


1.If A can do a piece of work in n days, then A's 1 day work=1/n 


2.If A's 1 day's work=1/n, then A can finish the work in n days.


Ex: If A can do a piece of work in 4 days,then A's 1 day's work=1/4.
    If A's 1 day’s work=1/5, then A can finish the work in 5 days 


3.If A is thrice as good workman as B,then: Ratio of work done by
A and B =3:1. Ratio of time taken by A and B to finish a work=1:3