Здравейте! Ако може малко помощ със тази задача дава ми 80/100 точки.Ето и условието https://softuni.bg/trainings/resources/officedocument/35379/exercise-problem-descriptions-programming-basics-bulgaria-october-2018/2158- 6-та задача.

https://judge.softuni.bg/Contests/Compete/Index/1161#5

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _06.Three_brothers
{
    class Program
    {
        static void Main(string[] args)
        {
            double B1 =double.Parse(Console.ReadLine());
            double B2 =double.Parse(Console.ReadLine());
            double B3 = double.Parse(Console.ReadLine());
            double F = double.Parse(Console.ReadLine());

            var Bs = 1 / (1 / B1 + 1 / B2 + 1 / B3);
            var BsR =(0.15 * Bs)+Bs;

            var timeleft = F - BsR;

            Console.WriteLine("Cleaning time: "+Math.Round(BsR,2));
            if (timeleft > 0)
                Console.WriteLine("Yes, there is a surprise - time left -> " + Math.Floor(timeleft) + " hours.");

            else
            {
                timeleft = Math.Abs(timeleft);
                Console.WriteLine("No, there isn't a surprise - shortage of time -> " + Math.Ceiling(timeleft) + " hours.");
            }
        
                     

        }
    }
}