A train passing a standing man takes 9 seconds, and it takes 21 seconds to pass a 240-meter long platform. Find the speed of the train in km/h. MCQ with Answer and Explanation

Explanation:
Total distance = 20 + 40 = 60 km. Total time = 20/5 + 40/10 = 4 + 4 = 8 hours. Average speed = 60 / 8 = 7.5 km/h.

Explanation:
When A covers 1000m, B covers 900m. When B covers 1000m, C covers 900m. So when B covers 900m, C covers 900 * (900/1000) = 810m. Therefore, when A covers 1000m, C covers 810m. A beats C by 1000 - 810 = 190m.

Explanation:
Let length of train be L. Speed = L/6. Also, Speed = (L + 210)/16. Equating them: L/6 = (L+210)/16 => 16L = 6L + 1260 => 10L = 1260 => L = 126 meters. Speed = 126 / 6 = 21 m/s. Speed in km/h = 21 * (18/5) = 378 / 5 = 75.6 km/h.