Module 2 · SSC GD Mathematics
Speed, Distance & Time
Relative speed, trains, boats & streams.
Relative Speed · Trains · Boats & Streams
Learning Objectives
- Understand the fundamental concepts of Speed, Distance & Time
- Apply key formulas and techniques to solve problems
- Practice with exam-level questions to build speed and accuracy
Key Concepts
Speed, Distance & Time for SSC GD & Agniveer
Speed, distance, and time problems are frequently asked in SSC GD and Agniveer mathematics sections. The basic relationship is Distance = Speed × Time. Questions involve trains, relative speed, average speed, and boats & streams.
Key Concepts
Basic Formula: Speed = Distance/Time. Units: 1 km/h = 5/18 m/s; 1 m/s = 18/5 km/h. Average Speed: For equal distances at speeds a and b: avg = 2ab/(a+b). For equal times: avg = (a+b)/2. Relative Speed: Towards each other: add speeds. Same direction: subtract speeds. Train Problems: Passing a pole: distance = train length. Passing a platform: distance = train length + platform length. Boats & Streams: Downstream = boat+stream; Upstream = boat-stream. Boat speed = (down+up)/2; Stream speed = (down-up)/2.
Solved Examples
Example 1
A train 200 m long passes a pole in 10 seconds. Find its speed in km/h.
a) 54 km/h b) 60 km/h c) 72 km/h d) 80 km/h
a) 54 km/h b) 60 km/h c) 72 km/h d) 80 km/h
Solution: c) 72 km/h. Speed = 200/10 = 20 m/s = 20×18/5 = 72 km/h.