More Questions from Problems on Trains

Two, trains, one from Howrah to Patna and the other from Patna to Howrah, start simultaneously. After they meet, the trains reach their destinations after 9 hours and 16 hours respectively. The ratio of their speeds is:

Aptitude Problems on Trains Difficulty: Medium
Choose an option
  • A
    3:2
  • B
    4:3
  • C
    5:4
  • D
    9:16

Answer

Correct Answer: 4:3

Explanation

Given Data

  • Two trains start simultaneously from opposite stations (Howrah ↔ Patna)
  • After meeting, they take 9 h and 16 h respectively to reach their destinations
  • Required: ratio of their speeds

Step 1: Relation between speeds and times after meetingLet speeds be v1 and v2; let meeting time from start be t.Distances before meeting: v1t and v2t.Remaining distance for Train 1 after meeting = v2t ⇒ time after meeting t1 = (v2t)/v1 = (v2/v1)t.Similarly, t2 = (v1/v2)t.Therefore, t1/t2 = (v2/v1)^2 ⇒ v1/v2 = √(t2/t1).

Step 2: Substitute valuest1 = 9 h, t2 = 16 hv1:v2 = √(16/9) = 4:3

Checks & Common Pitfalls

  • Do not take speeds inversely proportional to times directly; the square-root relation applies after meeting.
  • Both trains started together, so the derivation holds.

Final AnswerThe ratio of their speeds is 4:3.

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