Speed of boat in still water is 5 km/hr and speed of current is 1 km/hr. The boat takes total 75 min to go to some point and come back at the starting point. Find the distance between two points.

03 km

Speed of boat in downstream = 5 + 1 = 6 km/hr

Speed of boat in upstream = 5 - 1 = 4 km/hr

Let the distance b/w two points = 12 km  (LCM of 6 and 4)

Now,

Time taken by boat to go downstream = \(\frac{12}{6}\) = 2 hrs. = 120 min.

Time taken by boat to go upstream = \(\frac{12}{4}\) = 3 hrs. = 180 min.

Total time to go and return = 120 + 180 = 300 min

Hence, ATQ,

Total time = 75 min i.e. \(\frac{1}{4}\)th of 300

Therefore, distance = \(\frac{1}{4}\)th of 12 = 3 km.