Question

The distance between two stations is 400 km. A train goes from one station to the other with a speed of 50 km/hr and returns with a speed of 40 km/hr. What the average speed of the train during the journey?​

Answer 1

Given :-

◉ Distance d between two stations is 400 km.

◉ A train goes from one station to the other with a speed of s₁ = 50 Km/hr and returns with a speed s₂ = 40 Km/hr

To Find :-

◉ Average speed of the train during the journey.

Solution :-

If you carefully observe, It is given that the train travels the same distance twice.

So,

⇒ Total Distance Travelled = 400 + 400

⇒ D = 800 Km

Now, Let us find the total time taken which is sum of time the train took to go and return back respectively.

⇒ Total time taken = d/s₁ + d/s₂

⇒ T = 400/50 + 400/40

⇒ T = 40 + 10

⇒ T = 50 hr

Now, We know the total distance travelled and total time taken, So we can find the average speed

⇒ Avg. Speed = D / T

⇒ Avg. Speed = 800/50

⇒ Avg. Speed = 16 km/hr

Hence, The average speed is 16 km/hr