program TinhTuoiTrungBinh;
var
N, i, tuoi, tongTuoi: integer;
tuoiTrungBinh: real;
begin
writeln('Nhap vao so N ban: ');
readln(N);
tongTuoi := 0;
for i := 1 to N do
begin
writeln('Nhap vao tuoi cua ban thu ', i, ': ');
readln(tuoi);
tongTuoi := tongTuoi + tuoi...