A boatman goes 2 km against the current of the stream in 1 hour and goes 1 km along the current in 10 minutes. How long will it take to go 5 km in stationary water?
A boatman goes 2 km against the current of the stream in 1 hour and goes 1 km along the current in 10 minutes. How long will it take to go 5 km in stationary water?
Solution
✅ Correct Option: 3
Against current (upstream):
km in hour = km in minutes
Rate upstream = km/hr
Along current (downstream):
km in minutes = km/hr
Rate downstream = km/hr
If upstream speed = = speed in still water - speed of current =
And downstream speed = = speed in still water + speed of current =
Then:
... (1)
... (2)
Adding equations:
Therefore, speed in still water = km/hr
For km in still water:
Time = hours = hours = hour minutes