using System;

using System.Collections.Generic;

using System.Linq;

​

public class Program

{

        public static  void Main()

        {

            var list = new List<(Func<double, double>, double)> { ((x) => x * 2, 3), ((x) => x * 4, 5) };

            var result = list.Aggregate(0.0, (acc, tuple) => acc = acc + tuple.Item1(tuple.Item2));

​

            Console.Write(result);

        } 

​

}