using System;

public class Program

{

    public static void Main()

    {

        var date = new DateTime(2020,07,26);

        var dateOffset = 32;

        var startDate = date.Date.AddDays(dateOffset);

        var endDate = startDate.AddDays(1).AddMinutes(-1);

​

        Console.WriteLine($"startDate={startDate}");

        Console.WriteLine($"endDate={endDate}");

    }

}