A locomotive train 140 meters long passes a track milestone pole in 7 seconds flat. What is its speed in km/h? MCQ with Answer and Explanation

Explanation:
Speed = 150 / 6 = 25 m/s. In km/h = 25 * (18/5) = 90 km/h.

Explanation:
New speed = 7/9 of usual speed => New time = 9/7 of usual time. Difference = 2/7 of usual time = 12 minutes. 1/7 of usual time = 6 minutes => Usual time = 42 minutes.

Explanation:
Downstream speed = 4.5 + 1.5 = 6 km/h. Upstream speed = 4.5 - 1.5 = 3 km/h. Let distance be d. d/6 + d/3 = 2 => 3d/6 = 2 => d/2 = 2 => d = 4 km.