program AverageCalculation;
var
arr: array of Integer;
N, i, sum: Integer;
average: Real;
begin
Write('Enter the number of elements in the array: ');
Readln(N);
SetLength(arr, N);
sum := 0;
for i := 0 to N - 1 do
begin
Write('Enter element ', i + 1, ': ');
Readln(arr[i]);
sum := sum + arr[i];
end;
average := sum / N;
Writeln('Average: ', average:0:2);
end.

Пример работы программы:

Enter the number of elements in the array: 5
Enter element 1: 10
Enter element 2: 20
Enter element 3: 30
Enter element 4: 40
Enter element 5: 50
Average: 30.00