A typical silicon valley program ("fake it until you make it") would solve it like that:

print "Calculating...\n";
my $endtime = time + 25;
my $x;

while(time < $endtime) {
    $x++; # Todo: Implement better algo for wasting CPU cycles
}

open(my $ifh, '<', 'solution.txt') or die($!);
while((my $line = <$ifh>)) {
    print $line;
}
close $ifh;
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Sorry, couldn't resist ;-)