IF Statement in Forloop C++

hello if anyone help me pls do iam currently working on a for loop that shows your name score average and grade but i cant seem to make the grade appear if anyone know how pls do here is my code here should be the output Enter Your Name: Quiz 1 Quiz 2 Quiz 3 Average Grade <- this one dont appear its on the if statement in my code

using namespace std;
    int main(){
        int nos[5][3]; //multi-dimention
        int r, c;
        char name[20];
        int x[3];
        int av=0;

        char l;

         do{
           system("cls");

          for(r=0; r<5; r++){ //Row
          cout<<"Enter Your Name : ";
                       cin>>name;

           for(c=0; c<3; c++){ //Column                              
                                  cout<<"Enter Quiz "<<"["<<r<<"]"<<"["<<c<<"] : ";
                                         cin>>nos[r][c]; 

                                  }
                                 cout<<"Average : "<<(float)(nos[r][0]+nos[r][1]+nos[r][2])/3<<endl;
                                 av = ((float)nos[r][0]+nos[r][1]+nos[r][2])/3;
                                   if(av==0 && av<=74.99){
                                            cout<<"grade = 5.0"<<endl; }
                                   if(av ==75 && av<=76.99){
                                            cout<<"grade = 3.0"<<endl;  }       
                                   if(av ==77 && av<=79.99){
                                            cout<<"grade = 2.75"<<endl;  }
                                   if(av ==80 && av<=82.99){
                                            cout<<"grade = 2.50"<<endl; }
                                   if(av ==83 && av<=84.99){
                                            cout<<"grade = 2.25"<<endl; }
                                   if(av ==85 && av<=87.99){
                                            cout<<"grade = 2.0"<<endl; }
                                   if(av ==88 && av<=90.99){
                                            cout<<"grade = 1.75"<<endl; }
                                   if(av ==91 && av<=93.99){
                                            cout<<"grade = 1.50"<<endl;} 
                                   if(av ==94 && av<=96.99){
                                            cout<<"grade = 1.25"<<endl; }
                                   if(av ==97 && av<=100){
                                            cout<<"grade = 1.0"<<endl;}

                                  }



           cout<<"\nTry Another [Y/N] : ";
                             cin>>l;
                             }while(l!='N' && l!='n');
                                             getch();

                                             }