Model 3 Train Vs Bridge/Platform Section-Wise Topic Notes With Detailed Explanation And Example Questions

Answer: (b)

Let the length of train be x metre Speed = 90 km/hr

= ${90 × 5}/18$ metre /sec. = 25 metre/sec.

Distance covered in 60 sec.

= 25 × 60 = 1500 metres

Now, according to question,

2x = 1500 ⇒ x = 750 metre

Answer: (b)

Using Rule 10,

When a train croses a bridge, distance covered

= length of (bridge + train).

Speed of train = ${150 + 500}/30$

=$650/30 = 65/3$ m/sec.

Time taken to cross the 370m long platform

= ${370 + 150}/{65/3}$

= ${520 × 3}/65$ = 24 seconds

Answer: (b)

Using Rule 10,

Let the length of the train be x metres.

When a train corsses a platform it covers a distance equal to the sum of lengths of train and platform.

Also, the speed of train is same.

${x + 162}/18 = {x + 120}/15$

6x + 720 = 5x + 810

6x - 5x = 810 - 720

x = 90

The length of the train = 90m.

Answer: (b)

Speed of train = 54 kmph

= $({54 × 5}/18)$ m/sec.

= 15 m/sec.

Required time

= $\text"Length of train and bridge"/ \text" Speed of train"$

= $({200 + 175}/15)$ seconds

= $(375/15)$ seconds = 25 seconds

Answer: (c)

Using Rule 10,

Let the length of the train be x

According to the question,

${x + 122}/17 = {x + 210}/25$

25x + 3050 = 17x + 3570

25x - 17x = 3570 - 3050

8x = 520 ⇒ x = $520/8$ = 65 metres

Speed of the train

= ${65 + 122}/17 = 187/17$ metre/second

= 11 metre/second

= ${11 × 18}/5$ kmph = 39.6 kmph

Answer: (c)

Using Rule 10,

Let the length of train be x

According to the question,

${x + 600}/30$ = 30

x + 600 = 900

x = 900 - 600 = 300 m