Question

A train with speed 60km/h overtakes another train of length 225m in 72sec. If both train move towards each other then it takes 18 seconds to cross. Find the length of First train and speed of second train ​

Answer 1

Answer:

Let length of the train is X and length of the bridge is Y.

Speed of the First train = 60 km = (60 *5)/18 = 16.66 m/sec

Trains are moving in opposite direction, so their relative speed would be ,

S = 60 + 48 = 108 kmph = (108 *5)/18 = 30 m/sec

train crosses another train having half of its length in 15 sec . So, Train covered (X + X/2) = 3X/2 m in 15 sec.

Relative Speed = 3X/(2 *15)

3X/30 = 30 m/sec

X = 300 m

Length of the train = 300 m

Train crosses bridge in 51 sec. That is

Train needs to cover (300 + Y)m in 51 sec.

Speed of the train = (300 + Y)/51 m/sec

16.66 = (300 + Y)/51

850 = 300 + Y

Y = 850 - 300 = 550 m

Length of the bridge = 550 m.