# Find the speed of the stream from the speed of the man given in both upstream and downstream

• Last Updated : 19 Feb, 2022

A boat takes N1 hr to row a bot X1 km downstream of a river and take N2 hr to cover a distance of X2 km upstream. Find the speed of the stream.

Input: 3 15 2 5
Output: 17.5 km/hr

Input: 4 29 7 30
Output: 47 km/hr

Approach:

• Take input from users
• Calculate the rate of downstream and upstream. The rate can be calculated using the formula.

• Then, calculate the speed of the stream. It is given by the formula –

Below is the implementation.

## C++

 #includeusing namespace std; void rate(float down, float up){         // Stream rate    float rate = 0.5 * (down - up);    cout << rate <<  " Km/hr";} // Driver Codeint main(){       // Distance and time downstream    float N1 = 3;    float X1 = 15;     // Distance and time upstream    float N2 = 2;    float X2 = 5;     // Rate of downstream and upstream    float Rate_downstream = X1 / N1;    float Rate_upstream = X2 / N2;     rate(Rate_downstream, Rate_upstream);       return 0;} // This code is contributed by Surbhi Tyagi.

## Java

 /*package whatever //do not write package name here */ import java.io.*; public class GFG{     public static void rate(float down, float up){         // Stream rate    double rate = 0.5 * (down - up);    System.out.println(rate+ " Km/hr");}  // Driver Codepublic static void main(String args[]){   // Distance and time downstreamfloat N1 = 3;float X1 = 15; // Distance and time upstreamfloat N2 = 2;float X2 = 5; // Rate of downstream and upstreamfloat Rate_downstream = X1 / N1;float Rate_upstream = X2 / N2; rate(Rate_downstream, Rate_upstream);    }} // This code is contributed by sravankumar8128.

## Python3

 def rate(down, up):     # stream rate    rate = 0.5*(down - up)    print(rate, " Km/hr")  # Driver Code# Distance and time downstreamN1 = 3X1 = 15 # Distance and time upstreamN2 = 2X2 = 5 # Rate of downstream and upstreamRate_downstream = X1/N1Rate_upstream = X2/N2 rate(Rate_downstream, Rate_upstream)

## Javascript

 

## C#

 // C# program for the above approachusing System;class GFG {     static double rate(float down, float up)    {         // Stream rate        double rate = 0.5 * (down - up);        return rate;    }     // Driver Code    public static void Main()    {        // Distance and time downstream        float N1 = 3;        float X1 = 15;         // Distance and time upstream        float N2 = 2;        float X2 = 5;         // Rate of downstream and upstream        float Rate_downstream = X1 / N1;        float Rate_upstream = X2 / N2;         Console.WriteLine(            rate(Rate_downstream, Rate_upstream)            + " Km/hr");    }} // This code is contributed by Palak Gupta

Output:

1.25  Km/hr

Time Complexity: O(1)

Auxiliary Space: O(1)

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