Time and Work

beginner24 min read

The LCM (total-units) method for time-and-work problems, combining and subtracting work rates, the man-days idea, and the standard patterns: one person leaving partway, and alternating days.

What you will be able to do

Model a job as a fixed number of work units and each worker as a rate.
Combine rates for people working together and subtract rates to isolate one.
Use the man-days relationship for scaling workers, days and work.
Solve problems where a worker joins or leaves partway through.

What is inside this lesson

1Work as units, workers as rates
2The LCM (total-units) method
3The man-days relationship
4Worked example: two people together
5Worked example: isolating one worker
6Worked example: a worker leaves partway
7Common mistakes
8Quick revision

The lesson itself is for members

Reading the 8 sections above, the worked examples and the practice set is free — the whole knowledge base is on the free plan, along with flashcards, private notes and Ask Onely.

Create a free account Sign in