sprintf is probably what you want, yet give it a slightly altered input and it'll work:

use strict;
use warnings;
use Test::More qw(no_plan);

my $percent = sprintf("%d%%",(1/3)*100);
is($percent,"33%");
print "Result: $percent\n";

$percent = sprintf("%d%%",(1/30)*100);
is($percent,"3%");
print "Result: $percent\n";
[download]

Instead of '%02d%%', I now use '%d%%' which seems to be what you want.