从流的速度和时间与上游和下游的比率中找到人的速度

给定以公里/小时为单位的水流速度，程序以公里/小时为单位计算人的速度。假设这个人在河上游划船的时间是在河下游划船的时间的 n 倍（其中 n > 1）。
例子：

Input : 5.5 4
Output : speed of man is 9.16667 km/hr

Input : 4 3
Output : speed of man is 8 km/hr

使用的方法：
设人在静水中的速度 = x km/hr
设水流速度 = y km/hr
然后，下游速度 = (x + y) km/hr
上游速度 = (x – y) 公里/小时
让下游旅行所需的时间 = t hr
然后，逆流而上的时间 = nt hr
下游行驶距离 = (x + y)t km ————-(1)
逆行距离 = (x – y)tn km ————-(2)
从（1）和（2）
(x + y)t = (x – y)tn
给出： (x + y) = (x – y)n
给出：x + y = nx – ny
给出：nx – x = ny + y
这给出： x(n – 1) = y(n + 1)
给出： x = y(n + 1)/(n – 1)

C++

// C++ implementation
#include 
using namespace std;
 
// function to return speed of man
float speed_man(float y1, int n1)
{
    // return the speed of man in km/hr
    return ( y1 * (n1 + 1) / (n1 - 1) );
 
}
 
// Driver function
int main()
{
    // y is speed of stream in km/hr
    float y = 2.3;
    int n = 6;
     
    float speed = speed_man(y, n);
    cout << "speed of man is " << speed
        << " km/hr" << endl;
 
    return 0;
}

Java

// Java Implementation
import java.lang.*;
import java.util.*;
 
public class GeeksforGeeks {
 
    // function to return speed of man
    static float speed_man(float y1, int n1)
    {
        // x is speed of man
        return ( y1 * (n1 + 1) / (n1 - 1) );
          
    }
 
    // Driver function
    public static void main(String[] args)
    {
 
        // y is speed of stream in km/hr
        float y = 2.3f;
        int n = 6;
        float speed = speed_man(y, n);
         
        System.out.println("speed of man is "
                            + speed + " km/hr");
    }
}

Python3

# Python3 implementation to find
# the speed of man in km/hr
 
# Function to return speed of man
def speed_man(y1, n1):
 
    # return the speed of man in km/hr
    return (y1 * (n1 + 1) / (n1 - 1))
 
# Driver Code
 
# y is speed of stream in km/hr
y = 2.3; n = 6
     
speed = speed_man(y, n)
print("speed of man is ",
      "%.2f"%speed, " km/hr")
 
# This code is contributed by Anant Agarwal.

C#

// C# Implementation
using System;
 
public class GFG {
 
    // function to return speed of man
    static float speed_man(float y1, int n1)
    {
         
        // x is speed of man
        return ( y1 * (n1 + 1) / (n1 - 1) );
    }
 
    // Driver function
    public static void Main()
    {
 
        // y is speed of stream in km/hr
        float y = 2.3f;
        int n = 6;
        float speed = speed_man(y, n);
         
        Console.WriteLine("speed of man is "
                        + speed + " km/hr");
    }
}
 
// This code is contributed by vt_m.

Javascript

    // javascript Implementation
 
    // function to return speed of man
    function speed_man( y1,  n1)
    {
           
        // x is speed of man
         
        return ( y1 * (n1 + 1) / (n1 - 1) );
    }
     
   
    // Driver function
 
   
        // y is speed of stream in km/hr
        var y = 2.3;
        var n = 6;
        var speed = speed_man(y, n).toFixed(2)
           
        document.write("speed of man is "  + speed + " km/hr");
 

输出：

speed of man is 3.22 km/hr