>>682
それ、LINQいっこも関係ないような気が...
Func<Test, int> getScore = (x) =>
{
  if (Kyouka == "国語") return x.国語;
  if (Kyouka == "数学") return x.数学;
};
akaten = ListTest.Where(x => getScore(x) < 30 ).ToList().Count;