Tricks and Tips for Boat and Stream type Questions

Shortcut tricks on boats and streams are one of the most important topics in exams. These are the formulas and examples on Boats and Streams (Cyclist and the wind or Swimmer and stream) questions. These examples will help you to better understand shortcut tricks on boats and streams questions.

There are multiple types of questions asked from these topics.

• The speed of the boat in still water and the speed of stream will give in questions, You have to find the time taken by boat to go upstream and downstream.
  
• The speed of the boat in up and down stream will give in question,  you need to find the average speed of the boat.
• The speed of boat to go up or down the stream will give in question, you need to find speed of boat in still water and speed of stream
• The time taken by boat to reach a place in up and downstream will given in question, you need to find the distance to the place

Basic Formulas

• In water, the direction along with stream is called Downstream.
• The direction of the boat against the stream is called Upstream.
• The speed of boat or man in calm water which we denoted by sb.
• The speed of water or stream that denoted by sw. 
• Speed of boat in downstream (along the river) =  (sb + sw)
• Speed of boat in upstream (against the river) = (sb - sw) 
• Speed of boat in still water ss = ½(sb + sw)
• Speed of water current (Rate of stream) sc = ½(sb – sw)

Sample Questions

1. A man can row 18km/hr in still water. the speed of the man in downstream is thrice the speed in upstream. Find the rate of the stream?.
   

Let assume, Speed of man in upstream = x

Speed of man in downstream = 3x

Speed of man in still water ss = ½( x + 3x)

= 2x

We know speed of man in still water = 18

ie,  x = 9

Rate of stream = ½(27 – 9) =9 km/hr.