A goods train, travelling at constant speed, crossed two persons walking in the same direction (as that of the train) in 11.6 seconds and 11.8 seconds, respectively. The first person was walking at 5.85 km/h, while the second was walking at 6.3 km/h. What was the speed of the train (in km/h)?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is Option 3 i.e. 32.4.
Let the speed of the train be x km/hr and the length of the train be y m
According to the question,
⇒ x - 5.85 × =
⇒ y = (x - 5.85) × × 11.6.....(1)
⇒ x - 6.3 × =
⇒ y = (x - 6.3) × × 11.8.....(2)
From equations 1 and 2
⇒ (x - 5.85) × × 11.6 = (x - 6.3) × × 11.8
⇒ (x - 5.85) × 11.6 = (x - 6.3) × 11.8
⇒ 11.6x - 67.86 = 11.8x - 74.34
⇒ 0.2x = 6.48
⇒ x = 32.4