import java.util.Scanner;

public class ProjectCompletion {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        double totalWork = sc.nextDouble();
        double individualWorkRate = sc.nextDouble();
        int numberOfWorkers = sc.nextInt();
        double workRatePerWorker = sc.nextDouble();

        // Validate totalWork (> 0 and ≤ 1000)
        if (totalWork <= 0 || totalWork > 1000) {
            System.out.println("Invalid input");
            return;
        }

        // Validate individualWorkRate (> 0 and ≤ 100)
        if (individualWorkRate <= 0 || individualWorkRate > 100) {
            System.out.println("-1");
        } else {
            System.out.printf("%.1f\n", totalWork / individualWorkRate);
        }

        // Validate numberOfWorkers (≥ 1 and ≤ 100) and workRatePerWorker (> 0 and ≤ 100)
        if (numberOfWorkers < 1 || numberOfWorkers > 100 || workRatePerWorker <= 0 || workRatePerWorker > 100) {
            System.out.println("-1");
        } else {
            double groupRate = numberOfWorkers * workRatePerWorker;
            System.out.printf("%.1f\n", totalWork / groupRate);
        }
    }
}