for ( int GJ = 0; GJ <= 20; GJ++)
{
for ( int MJ = 0; MJ <=33; MJ++)
for (int XJ = 0; XJ <= 300;XJ++ )
if (5 * GJ + 3 * MJ + XJ / 3.0 == 100&&GJ+MJ+XJ==100) //3.0是关键
Console.WriteLine("公鸡" + GJ + ",母鸡" + MJ + ",小鸡" + XJ); ;
}