1 задание
uses crt;
var a: Array[1..255] of Integer;
n, sum, srsum: Integer;
begin
n := 1;
for var i := 1 to 255 do
if (i mod 2) 0 then
begin
if n = 20 then exit;
a[n] := i;
inc(n);
end;

for var i := 1 to 20 do
sum := sum + a[i];

writeln(srsum div 20);
end.

2 задание
uses crt;
var a: Array[1..15] of Integer;
i, k: Integer;
begin
Randomize;
for i := 1 to 15 do
begin
a[i] := Random(40) + 35;
end;
for i := 1 to 15 do
if (a[i] = 50) then inc(k);
writeln(k);
end.

Var
   A:array[1..20] of integer;
   i,S:integer;
Begin
Write('Исходный массив: ');
For i:= 1 to 20 do
    Begin
    A[i]:=i*2-1;
    Write(A[i],' ');
    S:=S+A[i]
    End;
WriteLn;
WriteLn('S = ',S);
WriteLn('Sr = ',S/20);
End.



Var A:array[1..15] of integer;
    i,k:integer;
Begin
Randomize;
k:=0;
Write('Исходный массив: ');
For i:= 1 to 15 do
    Begin
    A[i]:=random(41)+35;
    Write(A[i],' ');
    if (A[i]>=50)and(A[i]<=60) then k:=k+1
    End;
WriteLn;
WriteLn('k = ',k)
End.