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Syllabus
📋 SSC CGL
Subject:Tier-I Examination Syllabus

Time, Speed & Distance / Work

Syllabus Unit: Quantitative Aptitude

Why it matters

Chapter overview

Time-Speed-Distance and Time-and-Work share the same underlying skeleton: rate × time = quantity — speed × time = distance in one, work-rate × time = work done in the other. This topic builds unit-conversion fluency, relative speed for trains and boats, and the LCM-based work-rate method for pipes and cisterns, all of which SSC CGL tests as fast-turnaround word problems.

Tier-I Examination Syllabus Quantitative Aptitude 25% weightage
Live Animation1 / 4
1Convert Unitskm/h ↔ m/s consistently
2Identify DirectionSame or opposite
3Relative SpeedAdd or subtract speeds
4Apply D = S × TSolve for the unknown

1Speed, Distance & Relative Speed

Speed = distance/time is the entire chapter's DNA — relative speed just adds or subtracts two objects' speeds depending on their direction of travel.

Learning Objectives

  • Convert speed units fluently: km/h to m/s (× 5/18) and m/s to km/h (× 18/5).
  • Apply distance = speed × time and rearrange it to solve for whichever quantity is unknown.
  • Compute relative speed: add speeds for objects moving in opposite directions, subtract for the same direction.
  • Solve 'meeting point' and 'catch-up' problems using relative speed together with any given head start.

Key Terms

Speed Conversion Factorkm/h to m/s: multiply by 5/18. m/s to km/h: multiply by 18/5.
Relative Speed (opposite directions)The sum of the two individual speeds, used when objects move toward each other.
Relative Speed (same direction)The difference of the two individual speeds (faster − slower), used when one object chases another.
Catch-up TimeHead-start distance ÷ relative speed — the time for a faster object to catch a slower one with a lead.

Every TSD question is built from one identity, distance = speed × time, applied either directly or through a relative speed between two moving objects.

km/h → m/s: × 5/18 m/s → km/h: × 18/5

Relative speed

  • Opposite directions: relative speed = speed₁ + speed₂ (objects approach faster).
  • Same direction: relative speed = |speed₁ − speed₂| (the gap closes slower).
Catch-up time = Head-start distance ÷ (Relative speed, same direction)
Common MistakeAlways convert every given speed and distance to the same unit system (all m & m/s, or all km & km/h) before applying any formula — mixed units are the most common source of wrong answers here.