import java.util.Scanner;
public class ProjectCompletionCalculator 
{
    public static void main(String[] args) 
    {
        Scanner scanner = new Scanner(System.in);
        double totalWork = scanner.nextDouble();
        double individualWorkRate = scanner.nextDouble();
        int numberOfWorkers = scannernextInt();
        double workRatePerWorker = scanner.nextDouble();
        if (totalWork < 0) 
        {
            System.out.println("invalid input");
            return;
        }
        if (individualWorkRate <= 0) 
        {
            System.out.println("-1");
        } 
        else 
        {
            double individualTime = totalWork / individualWorkRate;
            System.out.println(individualTime);
        }
        if (numberOfWorkers <= 0 && workRatePerWorker <= 0) 
        {
            System.out.println("-1");
        } 
        else 
        {
            double groupTime = totalWork / (numberOfWorkers * workRatePerWorker);
            System.out.println(groupTime);
        }
    }
}