Program z1; const n = 15; Var k: array [1..n] of integer; i,s:integer;Begin randomize; for i:=1 to n do begin k[i]:=random(25)-20; write (k[i],' '); end; s:=0; for i:=1 to n do if ((k[i]>0)and(i mod 3 = 0)) then s:=s+k[i]; writeln; writeln('Сумма элементов - ',s);End.