Ah, much better! We don't care what your code looks like (actually, that's a lie) so long as you are prepared to take some advice and improve. This is lovely code - there is a ton of room for improvement. ;)

First off, always use strictures (use strict; use warnings;). Don't use $a and $b as variables - they are special (used by sort). Avoid the C style for loop - Perl's for loop is safer, clearer and cleaner.

Generally if you have parallel data try to use a single data structure for it so you don't have to double handle everything with the resultant duplication of code and much greater risk of errors.

Bearing that in mind consider:

use strict;
use warnings;

my $str1 = "a b c  d  e f  g  h i j";
my $str2 = "1 3 45 65 7 89 67 9 8 2";
my @seq  = split (' ', $str1);
my @arr  = split (' ', $str2);
my @data = map {[$seq[$_], $arr[$_]]} 0 .. $#seq;

my $beg  = 0;
my $end  = 0;

for (@data) {
    last unless $_->[1] < 15;
    $beg++;
}

for (reverse @data) {
    last unless $_->[1] < 15;
    $end++;
}

print join (' ', map {$data[$_][0]} $beg .. $#arr - $end), "\n";
print join (' ', map {$data[$_][1]} $beg .. $#arr - $end), "\n";
[download]