A boatman rows 24 km downstream and 12 km upstream, taking 2 hours for each leg of the journey. Find the speed of the boat in still water. MCQ with Answer and Explanation

Explanation:
Let original speed be s. 300 / s - 300 / (s + 10) = 1 => 300(10) = s(s + 10) => 3000 = s(s + 10). Solving s^2 + 10s - 3000 = 0 gives (s - 50)(s + 60) = 0. Since speed is positive, s = 50 km/h.

Explanation:
Speed = 14.4 km/h = 14.4 * (5/18) = 4 m/s. Time = 10 minutes = 600 seconds. Total distance = 4 * 600 = 2400 meters. Number of rounds = 2400 / 400 = 6 rounds.

Explanation:
Time taken to pass the platform alone = 17 - 8 = 9 seconds. Speed of train = 180 / 9 = 20 m/s.