有没有办法避免依赖于表达式的linq投影中的重复？

var students = new List<Student>
{
    new Student { Name = "Alice", Age = 20 },
    new Student { Name = "Bob", Age = 22 },
    new Student { Name = "Charlie", Age = 20 },
    new Student { Name = "David", Age = 21 },
    new Student { Name = "Eve", Age = 22 }
};

var result = from student in students
             group student by student.Age into ageGroup
             let averageAge = ageGroup.Average(s => s.Age)
             let count = ageGroup.Count()
             select new
             {
                 Age = ageGroup.Key,
                 AverageAge = averageAge,
                 Count = count
             };