Basic Formulas of Time and Work (Easy to Remember)

Before solving Time and Work questions, remember these simple relationships:

1. Work, Men, Days, and Time Relationship:
   Work ∝ (Men × Days)
   → M₁ × D₁ × T₁ / W₁ = M₂ × D₂ × T₂ / W₂

2. Work Efficiency Concept:
   Efficiency = 1 / Time taken
   (More efficiency → Less time required)

3. Work Done Formula:
   Work Done = Efficiency × Time

4. Combined Work Formula:
   If A can do a work in x days and B in y days,
   Then together, A & B = (1/x + 1/y) work per day

5. Time Taken When Working Together:
   Time = 1 ÷ (1/x + 1/y)

6. Inverse Proportion Rule:
   When work is constant,
   Men × Days = Constant

7. Pipes & Cistern (Filling or Emptying):

   • If one fills in x min and other empties in y min,
     Work done in 1 min = (1/x − 1/y)

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Quick Tip for Students

Always:

• Convert all units to the same type (hours, minutes, or days).

• Use LCM of time values to find total work easily.

• Remember: More men → less time; less men → more time.