Important Formulas

Time-work questions in quantitative aptitude typically involve calculating the time taken by a certain number of workers to complete a task. The formula for time-work questions is:

Time = Work / Efficiency


Time is the time taken to complete the task.

Work is the amount of work to be done.

Efficiency is the rate of work of each worker.

In time-work questions, the amount of work is usually expressed in terms of a unit of work such as a task, a job or a project, while the efficiency is often given as the rate of work of a single worker per unit time.

The formula can be modified depending on the type of question. For example, if the question involves more than one worker, the formula can be expanded to include the number of workers:

Time = Work / (Efficiency of one worker x Number of workers)

Alternatively, if the question involves the completion of a fraction of the work, the formula can be modified to find the time taken to complete that fraction:

Time = (Fraction of work x Total time required to complete the task) / Work


1. If a person can do a work in n numbers of days, then the person's 1 day's work = 1/n

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

3. If X is twice as good as a workman as Y, then

Ratio of work done by X and Y = 2 : 1

Ratio of times taken by X and Y to finish a job = 1 : 2