A train overtakes two persons walking along a railway track. The first one walks at 5.4km/h. The other one walks at 10.8 km/h. The train needs 5.1 and 6.8 secondsrespectively to overtake them. What is the speed of the train if both the persons arewalking in the same direction as the train?

Correct option is D

Given:

Speed of person 1 = 5.4 km/h

Speed of person 2 = 10.8 km/h

Time taken to overtake person 1 = 5.1 seconds

Time taken to overtake person 2 = 6.8 seconds

Formula Used:

Distance = Speed × Time

Solution:

Let the speed of the train be V meters

Now, Distance for both condition = length of the train

So, 

​$$(V-5.4)\times \frac{5}{18}\times5.1 = (V-10.8)\times \frac{5}{18}\times6.8 \\ \ \\ (V-5.4)\times 3 = (V-10.8)\times 4 \\ \ \\ 3V - 16.2 = 4V - 43.2 \\ \ \\ V = 27 \, km/h$$​​