Через while:
var
s, x, i: integer;
sr: real;
begin
s:=0; i:=0;
while i < 10 do
begin
readln(x);
s := s + x;
inc(i);
end;
sr := s / i;
writeln(sr);
end.
Через repeat:
var
s, x, i: integer;
sr: real;
begin
s:=0; i:=0;
repeat
readln(x);
s := s + x;
inc(i);
until i = 10;
sr := s / i;
writeln(sr);
end.
Через For:
var
s, x, i: integer;
sr: real;
begin
s:=0;
for i:=1 to 10 do
begin
readln(x);
s := s + x;
end;
sr := s / i;
writeln(sr);
end.