Pascal:
var a:array [1..30] of integer;
      i:integer;
      p:longint;
begin
  p:=1;
  randomize;
  a[1]:=random(21)+50;
  for i:=2 to 29 do a[i]:=random(100);
  a[30]:=random(21)+50;
  for i:=1 to 30 do write (a[i],' ');
  writeln;
  for i:=1 to 30 do
    if (a[i] in [10..99]) and (a[i] mod 2 = 0) and ((a[i] div 10) in [5..7]) then p:=p*a[i];
  writeln ('Proizvedenie: ',p);
  readln;
end.

C++:
#include <iostream>
#include <ctime>
#include <cstdlib>
using namespace std;

int main()
{
  int a[30],i;
  unsigned long long p = 1;
  srand (time(NULL));
  a[0] = rand()%70+50;
  for (i = 1; i<29; i++)
    a[i] = rand()%100;
  a[29] = rand()%7+50;
  for (i = 0; i<30; i++)
  {
    cout <<a[i] <<" ";
    if ((a[i]/10==5 || a[i]/10==6 || a[i]/10==7) && (a[i]>9 && a[i]<100) && a[i]%2==0)
      p*=a[i]; 
  }
  cout <<endl;
  cout <<"Proizvedenie: " <<p <<endl;
  return 0;
}