Two train 128 m and 132m long are running towards each other on parallel lines…
2023
Two train 128 m and 132m long are running towards each other on parallel lines at 42 km/hr and 30 km / hr respectively . In what time will they be clear of each other from the moment they meet?
- A.
13 sec
- B.
14 sec
- C.
15 sec
- D.
16 sec
Attempted by 1 students.
Show answer & explanation
Correct answer: A
Step-by-Step Solution
To calculate the time it takes for two trains to cross each other, we use the concept of relative speed and total distance.
Calculate Total Distance:
When two trains cross each other, the total distance covered is the sum of their lengths.
Total distance = 128 m + 132 m = 260 m.
Calculate Relative Speed:
Since the trains are running towards each other (opposite directions), their relative speed is the sum of their individual speeds.
Relative speed = 42 km/hr + 30 km/hr = 72 km/hr.
Convert Relative Speed to m/sec:
To convert km/hr to m/sec, multiply by 5/18.
Relative speed in m/sec = 72 * (5 / 18) = 4 * 5 = 20 m/sec.
Calculate Required Time:
Time = Total Distance / Relative Speed
Time = 260 m / 20 m/sec = 13 seconds.