Rules for Solving the Problems based on Time and Work

1) If a person can complete a work in $n$ days, then in $1$ day he does  $n^{th}$of the work. We have

$A\ Person's \ 1\ Day\ Work=$ $\frac{1}{Total\ number\ of\ days\ to\ complete\ the\ work}$

2) If a person completes of a work in $1$ day, then he requires $n$ number of days to complete the work

$Total\ no. \ of\ days\ to\ complete\ the\ work=$ $\frac{1}{A \ Person's \ 1\ Day\ Work}$

3) If part of the work has been done and the remaining part of the work has to be done by a person A, then

$No. \ of\ days \ to\ complete\ the\ work=$ $\frac{Remaining\ Part\ of\ the\ Work}{A's\ 1\ Day\ Work}$

4) If $A\ is\ m$ times as good ·a workman as $B$, then

i) Ratio of work done by $A \ and\ B$ in the same time $= m : 1$

ii) Ratio of time taken by $A \ and\ B$ to finish the work $=1: m$

5) If some persons work together to do a piece of work, then the money paid to them is divided among them in the ratio of their one day’s (or one hour’s) work.