c# - making a percent from a random number out of another number

        internal class GambleCommand : Command
{
    public GambleCommand()
        : base("roll", 3)
    {
    }

    protected override bool Process(Player player, RealmTime time, string[] args)
    {
        try
        {
            if (args.Length == 1)
            {
                int num = int.Parse(args[0]);
                Random rnd = new Random();
                string pl = player.Name;
                string rand = "";
                if (num < 0) rand = rnd.Next(num, 0).ToString();
                else rand = rnd.Next(0, num).ToString();
                decimal pc = num * rand / 100;
                foreach (Client i in player.Manager.Clients.Values)
                    {
                    i.SendPacket(new TextPacket
                    {
                        BubbleTime = 0,
                        Stars = -1,
                        Name = pl,
                        Text = "rolled a " + rand + " out of " + num + ". (" + pc + "%)"
                        });
                    }
                }
            }

        catch
        {
            Random rnd = new Random();
            string pl = player.Name;
            string rand = rnd.Next(0, 100).ToString();
            foreach (Client i in player.Manager.Clients.Values)
            {
                i.SendPacket(new TextPacket
                {
                    BubbleTime = 0,
                    Stars = -1,
                    Name = pl,
                    Text = "rolled a " + rand + " out of 100."
                });
            }
        }
        return true;
    }
}