Train ‘P’, running with a speed of 144 km/h, crosses a pole in 17 seconds. If the time taken by train ‘P’ to cross train ‘Q’ running with a speed of 72 km/h and coming from the opposite direction is 22.8 seconds, then find the length of train 'Q'.

This question was previously asked in
RRB PO Prelims Memory Based Paper (Held On: 3 August 2024 Shift 2)
View all RRB Officer Scale - I Papers >
  1. 688 meters
  2. 660 meters
  3. 448 meters
  4. 620 meters
  5. None of these

Answer (Detailed Solution Below)

Option 1 : 688 meters
Free
Banking Special English For All Exam Test
20 Qs. 20 Marks 12 Mins

Detailed Solution

Download Solution PDF

Train P crosses a pole in 17 seconds. The length of Train P is equal to the distance it covers in 17 seconds.

Speed of Train P = 144 km/h

Convert speed to m/s:

144 × 5/18 = 40 m/s

Length of Train P = Speed × Time

Length of Train P = 40 × 17 = 680 m

Train P and Train Q are moving in opposite directions. Their relative speed is the sum of their individual speeds.

Speed of Train P = 144 km/h = 40 m/s

Speed of Train Q = 72 km/h

Convert speed to m/s:

72 × 5/18 = 20 m/s

Relative speed = 40 + 20 = 60 m/s 

Train P takes 22.8 seconds to cross Train Q. The combined length of the two trains is equal to the distance covered at the relative speed in 22.8 seconds.

Combined Length = Relative Speed × Time = 60 × 22.8 = 1368 m

The combined length of Trains P and Q is 1368 m, and the length of Train P is 680 m. Therefore, the length of Train Q is:

Length of Train Q = Combined Length Length of Train P = 1368 - 680 = 688 m

Thus, the length of Train Q is 688 meters.

Latest RRB Officer Scale - I Updates

Last updated on Jul 3, 2025

-> The Institute of Banking Personnel Selection (IBPS) has officially released the Provisional Allotment under the Reserve List on 30th June 2025.  

-> As per the official notice, the Online Preliminary Examination is scheduled for 22nd and 23rd November 2025. However, the Mains Examination is scheduled for 28th December 2025. 

-> IBPS RRB Officer Scale 1 Notification 2025 is expected to be released in September 2025..

-> Prepare for the exam with IBPS RRB PO Previous Year Papers and secure yourself a  successful future in the leading banks. 

-> Attempt IBPS RRB PO Mock Test.  Also, attempt Free Baking Current Affairs Here

More Relative Speed Questions

More Speed Time and Distance Questions

Hot Links: teen patti rules teen patti all app teen patti master apk download