Playbook
Time and Work
46 q · 7% HARD · falling from 2.7 to 1.3 a paper. Work in rates or man-days, never in days directly, and the chapter is free marks.
- Questions in the bank
- 46
- q/paper (21 papers)
- 2.19
- Tagged HARD
- 7%
- Subtopics
- 4
Strand: Quick-Win
When you’ll see it
People or pipes finishing a job alone and together.
How this chapter is tested
46 questions, falling from 2.7 a paper in 2016-2020 to 1.3 in 2024-2026, at 7% HARD. Man-days and mixed gangs have never set a HARD question.
Work in rates (1/n of the job a day) or in man-days — never add days directly.
The sub-skills
The distinct skills inside the chapter, in the order to learn them.
Work rates
Rates add: together A and B finish in ab/(a + b) days.
Man-days
Men × days (× hours) is constant for one job.
Mixed gangs
Convert women or boys to men-equivalents first.
Pipes
A filling pipe is a positive rate, a leak negative.
Traps to expect
Distractor shapes this chapter reuses. The Traps page covers the ones that cut across chapters.
Adding days
A in 4 days and B in 6 days finish together in 2.4 days, not 5.
Learn it before you drill it
This chapter has full teaching notes — foundations, worked examples, self-checks and a mastery check for each subtopic. Read the notes once, then drill subtopic by subtopic below.
Time and Work notesDrill every Time and Work question
46 questions from the bank, across 4 subtopics.
Drill one subtopic at a time
The 4 subtopics, in teaching order.
- Work RatesDrill Work Rates
- Man-Days and Man-HoursDrill Man-Days and Man-Hours
- Men, Women and Equivalent WorkersDrill Men, Women and Equivalent Workers
- Pipes and CisternsDrill Pipes and Cisterns
Related playbooks
Often paired with this one — the technique or the trap overlaps. Drill these next.