Ответ:
--- PascalABC.NET 3.6.2 ---
#1
begin
var A := ArrRandom(70, -99, 99);
A.Println;
A.Where(p -> (Abs(p).ToString.Length = 2) and (p mod 10 = 3)).Aggregate(BigInteger.One, (p, q) -> p * q).Println;
end.
#2
begin
var A := ArrRandom(70, -999, 999);
A.Println;
A.Where(p -> (Abs(p).ToString.Length = 3) and (p mod 5 <> 0)).Average.Println;
end.
Объяснение: