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

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

    3.  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.