Problems on Time, Speed and Distance
October 20, 2022
Time and Work
October 24, 2022Â About this post
Boats and Streams is an application of the problems based on Time, Speed and Distance. In this topic, you will learn how to solve problems using the concept of relative speed. We have given some formulae along with solved question and answers that will help you in solving these problems. Once you complete this topic you must be able to solve problems based on stream speed, boat speed or a man rowing in a stream, time taken to to row etc using the formulae explained in this section.
Boats and Streams
1. Downstream:Â If a boat is travelling in the direction of the stream, the boat is said to be travelling downstream.
2. Upstream:Â If a boat is travelling opposite to the direction of the stream, the boat is said to be travelling upstream.
3. If the speed of the boat is $u$ km/hr and speed of the stream is $v$ km/hr, then
Speed Downstream(D) = $u\text{ }+\text{ }v$ km/hr
Speed Upstream(U) = $u\text{ }-\text{ }v$ km/hr
4. If speed downstream(D km/hr) and speed upstream(U km/hr) is given, then
Speed of the boat in still water(u) = $\frac{D\text{ }+\text{ }U}{2}$ km/hr
Rate of the stream(v) = $\frac{D\text{ }-\text{ }U}{2}$ km/hr
