Module 1 · Arithmetic
Chapter 8: Time & Work
Arithmetic
5 topics
What this chapter covers
The 5 topics below make up Time & Work on the CAT. Click any topic to open its notes, examples and practice test.
Study material & tests
📚 Study this chapter
Notes, worked examples and hint-guided practice for every topic.
Start learning →
🎯 Topic tests
8 auto-graded questions per topic, pulled from the question bank.
Practice by topic →
📝 Chapter test
25 fresh mixed-difficulty questions, timed, with full solutions.
Take chapter test →
Formula Reference Sheet
This chapter
Core rate & efficiency
| Work rate | Rate = Work ÷ Time (units per day) |
|---|---|
| Total work (LCM trick) | Total work = LCM of the given days |
| Efficiency from days | Efficiency = Total work ÷ days |
| Combined time | Time = Total work ÷ (sum of efficiencies) |
| Efficiency ∝ 1/Time | If A is k× as fast as B ⇒ A takes 1/k of B’s time |
CAT power-tools
| Two together (classic) | Time = (a × b) ÷ (a + b) days |
|---|---|
| Man-days (work equivalence) | M1 × D1 = M2 × D2 (same job) |
| Full chained formula | M1·D1·H1 / W1 = M2·D2·H2 / W2 |
| Wages share | Wages split in the ratio of work done (= ratio of efficiencies × days worked) |
| Leak / negative work | Effective rate = inflow rate − leak rate |
CAT reference
🖩 Graphing Calculator