I think this do what you need,

use strict;
use warnings;
my @input = <DATA>;
chomp @input;
my ($max, $s_max) = sort { $b<=>$a} @input;
print $max,$",$s_max,$/;
__DATA__
0.2430
0.0830
0.1320
0.0920
0.0180
0.0880
0.3440
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