Linq Average Rate.txt

var reviews = new List<Review> { 
    new Review { Rate = 4, value = "AAA" },
    new Review { Rate = 8, value = "BBB" },
    new Review { Rate = 10, value = "CCC" }
};

Console.WriteLine((float)reviews.Sum(x => x.Rate) / reviews.Count); // 7.333333
Console.WriteLine(reviews.Average(x => x.Rate)); // 7.33333333333333