1. Work from Days:
If A can do a piece of work in n days, then A's 1 day's work = 1/n .
2. Days from Work:
If A's 1 day's work = 1/n , then A can finish the work in n days.
3. Ratio:
If A is thrice as good a workman as B, then:
Ratio of work done by A and B = 3 : 1.
Ratio of times taken by A and B to finish a work = 1 : 3.
