Correct Answer - Option 4 : 705 m
Rajan sitting inside a train travelling at a speed of 108 km/h crosses another train running in the same direction in 47 seconds.
The speed of the slower train is 25 m/s and the length of the faster train is two times the length of the slower train.
Formula used :
Time = Distance/Speed
Let the length of the slower train be 'L' m
Speed of the faster train in m/s = 108 × (5/18) = 30 m/s
Speed of slower train = 25 m/s
According to the question
47 = (length of the slower train)/Relative speed
⇒ 47 = L/(30 - 25) (when train move in same direction relative speed is the difference of the speeds)
⇒ l = 47 × 5 = 235 m
Now length of faster train = 2 × L = 2L
⇒ 470 m
Total length of both the trains = 235 + 470 = 705 m
∴ The length of both the trains will be 705 m