这道题应分多种情况，下面是给出个参考 希望对你有帮助
void main()
{
   
    int x,y,z;
    float i;
    const float m_x=0.1,m_y=1.5,m_z=3;
    cout<<"只买单种鸡蛋情况明显不成立"<<endl<<endl;
   
    cout<<"买鸡蛋和鸭蛋情况"<<endl;
    for(x=0;x<=100;x++)
    {
        for(y=0;y<=100;y++)
        {
            i=x*m_x+y*m_y;
            if(((x+y)==100)&&(i==100))
                cout<<"鸡蛋"<<x<<"鸭蛋"<<y<<endl<<endl;
               
        }
    }
    if(!(((x+y)==100)&&(i==100)))
        cout<<"买鸡蛋和鸭蛋情况不成立"<<endl<<endl;
    cout<<"买鸡蛋和鹅蛋情况"<<endl;
    for(x=0;x<=100;x++)
    {
        for(z=0;z<=100;z++)
        {
            i=x*m_x+z*m_z;
            if(((x+z)==100)&&(i==100))
            {    cout<<"鸡蛋"<<x<<"鹅蛋"<<z<<endl;}
            
        }
    }
    if(!(((x+z)==100)&&((x*m_x+z*m_z)==100)))
        cout<<"买鸡蛋和鹅蛋不成立"<<endl<<endl;

   
    cout<<"买鸭蛋和鹅蛋情况"<<endl;
    for(y=0;y<=100;y++)
    {
        for(z=0;z<=100;z++)
        {
            if(((z+y)==100)&&((y*m_y+z*m_z)==100))
            {    cout<<"鸭蛋"<<y<<"鹅蛋"<<z<<endl;}
            
        }
    }
    if(!(((z+y)==100)&&((y*m_y+z*m_z)==100)))
        cout<<"买鸭蛋和鹅蛋不成立"<<endl<<endl;

   
    cout<<"三种蛋都买的情况"<<endl;
    for(x=0;x<=100;x++)
    {
        for(y=0;y<=100;y++)
        {
             for(z=0;z<=100;z++)
             {
                  i=x*m_x+y*m_y+z*m_z;
                 if((x+y+z)==100&&(i==100))
                     cout<<"鸡蛋："<<x<<"鸭蛋："<<y<<"鹅蛋："<<z<<endl;
             }
        }
    }

}