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Program to find the Speed of train as per speed of sound

  • Last Updated : 08 Apr, 2021

Two guns were fired from same place at an interval of ‘X’ minutes. A person who is approaching the shooting place by train hears the shooting sound at an interval of ‘Y’ minutes, The task is to find the ‘S’ i.e speed of the train.
Note: Speed of the sound in air is 330m/s in a fixed value.

Examples: 

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Input: X = 14 min, Y = 13.5 min 
Output: S = 44 km/hr



Input: X = 8 min, Y = 7.2 min 
Output: S = 132 km/hr 
 

Approach: Take the first example, 

  • Distance covered by the train in Y minutes 
    = Distance covered by the sound in (X – Y) minutes 
    = 330 * (X – Y) * 60 minutes (Distance = speed of sound * time)
  • Speed of the train 
    = (330 * (X – Y) * 60 ) / Y (Speed = distance / time) 
    = (330 * 60 * (X – Y)) / 1000 * (60 / y) 
    = 1188 [ (X – Y) / Y] km/hr
  • Now, According to 1st example
    Time difference i.e (X – Y) = 14.00 – 13.30 = 30sec 
    Speed of train = 1188 * [ (14 – 13.5) / 13.5 ] = 44km/hr
  • This can be calculated by using the below formula:
     

Below is the implementation of the above approach.  

C++




// C++ implementation of the approach
 
#include <bits/stdc++.h>
using namespace std;
 
// Function to find the
// Speed of train
float speedOfTrain(float X, float Y)
{
 
    float Speed = 0;
 
    Speed = 1188 * ((X - Y) / Y);
 
    return Speed;
}
 
// Driver code
int main()
{
    float X = 8, Y = 7.2;
 
    // calling Function
    cout << speedOfTrain(X, Y)
         << " km/hr";
 
    return 0;
}

Java




// Java implementation of the approach
class GFG
{
 
    // Function to find the
    // Speed of train
    static int speedOfTrain(float X, float Y)
    {
        float Speed;
 
        Speed = 1188 * ((X - Y) / Y);
 
        return (int)Speed;
    }
 
    // Driver code
    public static void main(String[] args)
    {
        float X = 8f, Y = 7.2f;
 
        // calling Function
        int result = (speedOfTrain(X, Y));
        System.out.println(result + " km/hr");
    }
}
 
// This code is contributed by PrinciRaj1992

Python3




# Python3 implementation of the approach
from math import ceil
 
# Function to find the
# Speed of train
def speedOfTrain(X, Y):
    Speed = 0
 
    Speed = 1188 * ((X - Y) / Y)
 
    return Speed
 
# Driver code
if __name__ == '__main__':
    X = 8
    Y = 7.2
 
    # calling Function
    print(ceil(speedOfTrain(X, Y)),
                   end = " km/hr")
 
# This code is contributed by
# Surendra_Gangwar

C#




// C# implementation of the approach
using System;
 
class GFG
{
 
    // Function to find the
    // Speed of train
    static int speedOfTrain(float X, float Y)
    {
        float Speed;
 
        Speed = 1188 * ((X - Y) / Y);
 
        return (int)Speed;
    }
 
    // Driver code
    public static void Main()
    {
        float X = 8f, Y = 7.2f;
 
        // calling Function
        int result = (speedOfTrain(X, Y));
        Console.Write(result + " km/hr");
    }
}
 
// This code is contributed by anuj_67..

Javascript




<script>
 
// Javascript implementation of the approach
 
// Function to find the
// Speed of train
function speedOfTrain(X, Y)
{
    var Speed;
 
    Speed = 1188 * ((X - Y) / Y);
 
    return Speed;
}
  
// Driver Code
var X = 8, Y = 7.2;
 
// Calling Function
var result = (speedOfTrain(X, Y));
document.write(Math.round(result) + " km/hr");
 
// This code is contributed by Ankita saini
                     
</script>
Output: 
132 km/hr

 




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