A train, travelling at a uniform speed for 360 km, would have taken 48 mins less to travel the same distance, if its peed were 5 km/hr more. Find the original speed of the train.

Question

Philoid · Accepted Answer

Let the original speed of the train be x km/hr

Then, the increased speed of the train = (x + 5) km/hr

According to question,

[* ]

⇒

⇒ [5(360x + 1800) – (360x)] = 4x (x + 5)

⇒ 4x² + 20x – 9000 = 0

⇒ x² + 5x – 2250 = 0

By using the quadratic formula,

∴ The original speed of the train is 45 km/hr. (* Speed cannot be negative)