uses crt;
var i,n,c,s:longint;
a:array[1..100] of longint;
begin
clrscr;
write('nhap so ptu:');readln(n);
for i:=1 to n do
begin
 write('A[',i,']=');
 readln(a[i]);
 if (a[i] >30) and (a[i] <50) then
 begin
  s:=s+a[i];
  c:=c+1;
 end;
end;
writeln('co ',c,' so thoa man dieu kien');
writeln('tong cac so thoa man dieu kien:',s);
readln;
end.

(mong dc 5*+hay nhất)

uses crt;
var i,s,d: integer;
    a: array[1..5] of integer;
begin
clrscr;
    for i:=1 to 5 do
    begin
        write('Nhap so thu ',i,': ');
        readln(a[i]);
        if (a[i]>30) and (a[i]<50) then
        begin
            d:=d+1;
            s:=s+a[i];
    end;
    if d=0 then write('Khong co so nao thoa man!') else
    begin
        writeln('Co ',d,' so  thoa man');
        writeln('Tong cac so thoa man la: ',s);
    end;
    readln
end.