use strict;
use warnings;

my $width = 11;

my $le = "lethal_results.txt";
open(LE , "<", $le)
   or die("Unable to open file $le: $!\n");

while (<LE>) {
   chomp;
   my @line = split(/\s+/, $_);
   if ($line[4] >= 50) {
      printf("%s%${width}s%${width}s%\t\t%.6g\n",
         @line[0,1,2,4]
      );
   }
}