Train Problem (Question)
Important Train Based Formulas : Click Here
Concept: Two Trains Crossing Each Other : āϧāĻžā§°āĻŖāĻž: āĻĻā§āĻāĻž ā§°ā§āϞ āĻĒā§°āϏā§āĻĒā§° āĻ āϤāĻŋāĻā§ā§°āĻŽ āĻā§°āĻž
When two trains cross each other, the total distance covered is the sum of their lengths. āϝā§āϤāĻŋā§āĻž āĻĻā§āĻāĻž ā§°ā§āϞ⧠āĻĒā§°āϏā§āĻĒā§° āĻ āϤāĻŋāĻā§ā§°āĻŽ āĻā§°ā§, āϤā§āϤāĻŋā§āĻž āĻŽā§āĻ āĻĻā§ā§°āϤā§āĻŦ āĻš’āϞ āĻĻā§ā§ā§ ā§°ā§āϞ⧰ āĻĻā§ā§°ā§āĻā§āϝ⧰ āϝā§āĻāĻĢāϞāĨ¤
Total distance = Lâ + Lâ : āĻŽā§āĻ āĻĻā§ā§°āϤā§āĻŦ = Lâ + Lâ
Relative Speed (Opposite Direction) : āĻāĻĒā§āĻā§āώāĻŋāĻ āĻāϤāĻŋ (āĻŦāĻŋāĻĒā§°ā§āϤ āĻĻāĻŋāĻļāϤ)
If two trains move in opposite directions, their relative speed is the sum of their speeds. āϝāĻĻāĻŋ āĻĻā§āĻāĻž ā§°ā§āϞ āĻŦāĻŋāĻĒā§°ā§āϤ āĻĻāĻŋāĻļāϤ āĻāϞā§, āϤā§āύā§āϤ⧠āĻāĻĒā§āĻā§āώāĻŋāĻ āĻāϤāĻŋ āĻš’āϞ āĻĻā§ā§ā§ āĻāϤāĻŋā§° āϝā§āĻāĻĢāϞāĨ¤
Relative Speed = Sâ + Sâ : āĻāĻĒā§āĻā§āώāĻŋāĻ āĻāϤāĻŋ = Sâ + Sâ
Time Formula: āϏāĻŽā§ā§° āϏā§āϤā§ā§°
Time = L1 + L2 / S1 + S2 āϏāĻŽā§ = L1 + L2 / S1 + S2
Given Data : āĻĒā§ā§°āĻĻāϤā§āϤ āϤāĻĨā§āϝ
Speed of Train 1 (Sâ) = 110 m/s : Train 1 ā§° āĻāϤāĻŋ = 110 āĻŽāĻŋ/āĻā§
Speed of Train 2 (Sâ) = 140 m/s : Train 2 ā§° āĻāϤāĻŋ = 140 āĻŽāĻŋ/āĻā§
S1 + S2 = 110 + 140 = 250 m/s
Case 1: Numerical Problem : āĻāĻŖāĻŋāϤā§ā§ āĻāĻĻāĻžāĻšā§°āĻŖ
Length of Train 1 (Lâ) = 400 m : Train 1 ā§° āĻĻā§ā§°ā§āĻā§āϝ = 400 āĻŽāĻŋ
Length of Train 2 (Lâ) = 600 m : Train 2 ā§° āĻĻā§ā§°ā§āĻā§āϝ = 600 āĻŽāĻŋ
Soln : āϏāĻŽāĻžāϧāĻžāύ
L1 + L2 = 400 + 600 = 1000 m L
Time = 1000 / 250 = 4 seconds
Final Answer : āĻā§ā§āĻžāύā§āϤ āĻāϤā§āϤ⧰ : Time taken by the two trains to cross each other = 4 seconds : āĻĻā§āĻāĻž ā§°ā§āϞ⧠āĻĒā§°āϏā§āĻĒā§° āĻ āϤāĻŋāĻā§ā§°āĻŽ āĻā§°āĻŋāĻŦāϞ⧠āϞā§ā§ąāĻž āϏāĻŽā§ = ā§Ē āĻā§āĻā§āĻŖā§āĻĄ
Key Exam Tips (SSC / HSLC) : āĻĒā§°ā§āĻā§āώāĻžā§° āĻā§ā§°ā§āϤā§āĻŦāĻĒā§āϰā§āĻŖ āĻāĻŋāĻĒāĻ
- Crossing each other → Add lengths : āĻ āϤāĻŋāĻā§ā§°āĻŽ āĻā§°āĻž → āĻĻā§ā§°ā§āĻā§āϝ āϝā§āĻ
- Opposite direction → Add speeds : āĻŦāĻŋāĻĒā§°ā§āϤ āĻĻāĻŋāĻļ → āĻāϤāĻŋ āϝā§āĻ
- Same direction → Subtract speeds : āĻāĻā§āĻāĻž āĻĻāĻŋāĻļ → āĻāϤāĻŋ āĻŦāĻŋā§ā§āĻ
- km/h to m/s conversion → × 5/18 : km/h ā§° āĻĒā§°āĻž m/s āϞ⧠→ × 5/18
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Q. A train of length X m, moving at a speed of 59 m/sec, crosses a railway platform of length 279 m in 9 seconds. Find the value of X.
A. 262 B. 256 C. 252 D. 253
Solution
Distance covered in 9 seconds:
While crossing a platform:
Ans: C. 252 m
Trick:
Train : Bridge Problem
Q. A person drives a car at a speed of 21 km/h and crosses a bridge in 18 minutes. What is the length of the bridge ?
A. 15.2 km B. 4.7 km C. 2.5 km D. 6.3 km
Solution
Formula: Distance = Speed × Time
Convert minutes into hours: 18 minutes = 18/60 = 0.3 hour
Now,
Distance = 21 × 0.3 = 6.3 km
Ans: (D) 6.3 km
Trick
Distance = Speed × Time (Always remember to convert minutes into hours before calculating.)