A crew row a boat 24 km upstream and 36 km downstream, taking 4 hours for each separate direction. Find the speed of the current stream. MCQ with Answer and Explanation

Explanation:
Let length of train be L. Speed = L/30. Also, Speed = (L+110)/40. So L/30 = (L+110)/40 => 4L = 3L + 330 => L = 330 meters.

Explanation:
Relative speed = 100 / 6 = 50/3 m/s = (50/3) * (18/5) = 60 km/h. Since the train passes him from behind (same direction), Relative Speed = Speed of train - Speed of man => 60 = Speed of train - 5 => Speed of train = 65 km/h.

Explanation:
New speed = 4/5 of usual speed => New time = 5/4 of usual time. Difference = 1/4 of usual time = 15 minutes. Normal time = 15 * 4 = 60 minutes.