Train Speed and Distance Problems

A train goes from A to B at a speed of 20 km/h and returns from B to A by the same route at 30 km/h. The average speed (in km/h) of the train during the two-way journey is:

• 24

• 23

• 25

• 22

Answer explanation

The average speed for a round trip is calculated using the formula: Average Speed = 2 * (Speed1 * Speed2) / (Speed1 + Speed2). Here, it is 2 * (20 * 30) / (20 + 30) = 24 km/h. Thus, the correct answer is 24.

A train travels at a speed of 30 km/h for 6 hours and at 45 km/h for 4 hours. What is the average speed of the train during these 10 hours?

• 35 km/h

• 36 km/h

• 40 km/h

• 37 1/2 km/h

Answer explanation

To find the average speed, calculate total distance and total time. Distance = (30 km/h * 6 h) + (45 km/h * 4 h) = 180 km + 180 km = 360 km. Total time = 10 h. Average speed = 360 km / 10 h = 36 km/h, which is the correct answer.

An express train travelled at an average speed of 100 km/h stopping for 3 min after every 75 km. How much time it took the express train to travel 600 km?

• 370 min

• 381 min

• 384 min

• 308 min

Answer explanation

The train travels 600 km at 100 km/h, taking 6 hours (360 min). It stops 8 times (3 min each) for a total of 24 min. Thus, total time = 360 + 24 = 384 min. However, correcting for the last segment, the total is 381 min.

If a train runs at an average speed of 42 km/h, then it covers a certain distance in 45 min. What is the speed at which the train must run to reduce the time of the same journey to 35 min?

• 52.5 km/h

• 49 km/h

• 52 km/h

• 54 km/h

Answer explanation

The train covers distance in 45 min at 42 km/h, which is 31.5 km. To cover this in 35 min, the speed must be 31.5 km / (35/60) h = 54 km/h. Thus, the required speed is 54 km/h.

The uninterrupted average speed of a train is 45 km/hr and the interrupted average speed is 36 km/hr. Find the average speed of the train of its stoppages?

• 9

• 15

• 12

• 10

Answer explanation

To find the average speed during stoppages, use the formula: Average Speed = (Uninterrupted Speed + Interrupted Speed) / 2. Thus, (45 + 36) / 2 = 40. The difference from uninterrupted speed (45 - 40) gives 5 km/hr. The average speed of stoppages is 12 km/hr.

The distance between two stations is 100 km. A train covers the distance at 80 km/hr going and while returning it covers the distance at 3/4 speed of previous speed. What is the average speed of the train?

• 68.5 km/h

• 68.6 km/h

• 70.3 km/h

• 70.4 km/h

Answer explanation

The train's return speed is 60 km/hr (3/4 of 80 km/hr). Total time for the journey is 1.25 hours going and 1.67 hours returning. Average speed = total distance / total time = 100 km / 1.92 hr = 68.6 km/h.

A train crosses a 155 metre long platform in 16 seconds and a 195 metre long platform in 18 seconds. What is the average speed of train?

• 66 km/h

• 72 km/h

• 75 km/h

• 69 km/h

Answer explanation

The train's length can be calculated from the time taken to cross each platform. For the 155m platform in 16s, speed = (155 + train length)/16. For the 195m platform in 18s, speed = (195 + train length)/18. Solving gives average speed = 72 km/h.

A train moves 1 km an uniform speed of 240 km/hr and next 1 km at 80 km/hr. What is the average speed of train?

• 160 km/hr

• 180 km/hr

• 120 km/hr

• 200 km/hr

Answer explanation

To find the average speed, use the formula: average speed = total distance / total time. The total distance is 2 km. Time for 1 km at 240 km/hr is 1/240 hr, and at 80 km/hr is 1/80 hr. Total time = 1/240 + 1/80 = 1/60 hr. Average speed = 2 km / (1/60 hr) = 120 km/hr.

A train covers first 40 km of distance at 80 km/hr and second 30 km of distance in 60 km/hr. Then find its average speed?

• 62 km/hr

• 64 km/hr

• 65 km/hr

• 70 km/hr

Answer explanation

To find the average speed, calculate total distance (40 km + 30 km = 70 km) and total time (0.5 hr + 0.5 hr = 1 hr). Average speed = total distance / total time = 70 km / 1 hr = 70 km/hr. Thus, the correct answer is 70 km/hr.

A train covered a certain distance at a uniform speed. If the train had been 12 km/h faster, it would have taken 8 hours less than the scheduled time. If the train were slower by 12 km/h, the train would have taken 12 hours more than the scheduled time. Find the length of the journey (in km).

• 1480

• 2860

• 2880

• 1440

Answer explanation

Let the distance be D km and speed be S km/h. From the problem, we have two equations: (D/S) - (D/(S+12)) = 8 and (D/S) - (D/(S-12)) = -12. Solving these gives D = 2880 km, which is the correct answer.