Two trains are moving in the same direction at the speed of 34 Km/hr and 86 Km/hr, there lengths are 300 meters and 480 meters respectively. What will be the time taken by faster train to cross the slower train?
a) 36 second
b) 54 second
c) 60 seconds
d) 48 seconds
Ans : b) 54 second
SSC Constable GD Exam Paper : Elementary Mathematics
Solution :
we need to calculate how long it will take for the faster train to completely cross the slower train.
Step 1: Relative Speed
Since both trains are moving in the same direction, we need to find the relative speed between the two trains. The relative speed is the difference between their speeds.
Relative speed=86 km/hr−34 km/hr=52 km/hr
Now, convert the relative speed into meters per second, because the lengths of the trains are in meters.
Step 2: Total Distance to be Covered
The faster train has to cross the entire length of the slower train, plus its own length. Therefore, the total distance to be covered is the sum of the lengths of both trains:
Total distance=300 meters+480 meters=780 meters
Step 3: Time Taken to Cross
Time is calculated by dividing the total distance by the relative speed:
Time = 
Thus, the faster train will take approximately 54 seconds to cross the slower train.