Question

A train travels at a certain average speed for a distance of 132 km and then travels a distance of 140 km at an average speed of 4 km/h more than the initial speed. If it takes 4 hours to complete the whole journey, what was the initial average speed? Determine the time taken by train to cover the distances separately.

Answer 1

Let the initial average speed of the train be x km/hr 

Therefore 132/x + 140/x+4 = 4 

⇒ 4x² − 256x − 528 = 0 

 or x² − 64x − 132 = 0 

⇒ (x − 66)(x + 2) = 0 

⇒ x = 66, x ≠ −2 

Initial average speed of train= 66 km/hr 

Time taken to cover the distances separately=132/66 & 140/70 i.e. 2 hours each