A locomotive express train passes a milestone column track point in 15 seconds flat. If the speed index of the train records at 72 km/h, find the length of the train layout. MCQ with Answer and Explanation

Explanation:
Let total distance be 100 km. First part: 40 km at 40 km/h => time = 1 hour. Remaining distance = 60 km. Second part: 50% of 60 = 30 km at 30 km/h => time = 1 hour. Remaining distance = 30 km. Third part: 30 km at 15 km/h => time = 2 hours. Total time = 1 + 1 + 2 = 4 hours. Average speed = 100 / 4 = 25 km/h.

Explanation:
Ratio of times is the inverse of the ratio of speeds: 1/2 : 1/3 : 1/4. Multiplying by the LCM (12), we get 6 : 4 : 3.

Explanation:
Speed = 18 km/h = 5 m/s. Time = 10 minutes = 600 seconds. Total distance covered = 5 * 600 = 3000 meters. Number of rounds = 3000 / 600 = 5 rounds.