Important Concepts & Tricks – Boat and Stream
Up Stream – It means the boat is moving against the direction of the stream.
Down Stream – It means the boat is moving in the direction of the stream.
- Stream means current i.e. the speed of water.
- When we say speed of boat/swimmer/steamer, we mean the speed in still water.
- Speed of Boat/Steamer/swimmer is always considered greater than the speed of current.
Let the Speed of Boat = x km/hr
Speed of Stream/current = y km/hr. Then-
Speed of Boat in Upstream = (x – y) km/hr
Speed of Boat in downstream = (x + y) km/hr
Speed of Boat = 1/2 (Speed of Boat in Upstream + Speed of Boat in downstream)
Speed of Stream = 1/2 (Speed of Boat in downstream – Speed of boat in Upstream)
Q- 1> A man can row upstream at 6 km/hr and downstream at 10 km/hr. Find the speed of man and the speed of current.
Upstream Speed= 6 km/hr
Downstream Speed = 10 km/hr
Man’s Speed = (10 + 6)/2 = 8 km/hr (Ans.)
Current’s Speed = (10 – 6)/2 = 2 km/hr (Ans.)