Question

A schedule speed of 45 km/h is required between two stops 1.5 km apart. If the stop is 20 sec duration, what is the actual time of run for the train?
1. 120 sec
2. 60 sec
3. 100 sec
4. 80 sec

Answer 1

Correct Answer - Option 3 : 100 sec

Schedule Speed: 

The ratio of the distance covered between two stops to the total time of the run including the time for the stop is known as schedule speed.

It is denoted with Vs

\({V_s} = \frac{D}{{{T_s}}}\)

Where,

D is the distance between stops

Ts is the scheduled time in hours

T_s = Total time of run + time for stop (T_r + T_h)

Calculation:

Given, 

V_s = 45 km/h

= 45 × (5 / 18)

= 25 / 2 (m/sec)

D = 1.5 km 

= 1.5 × 1000

= 1500 m

Time for stop T_h = 20 secs

Total time of run T_r = ?

\({V_s} = \frac{D}{{{T_s}}}\)

25 / 2 = 1500 / (T_r + 20)

⇒ T_r + 20 = 120

⇒ T_r = 100 secs

Therefore, the actual time of run for the train is 100 secs