use strict;
use warnings;
use Data::Dump::Streamer;

my @class = (40, 40, 40, 183, 183, 259, 244, 503);
my @qty = (260, 234, 211, 301, 401, 321, 210, 451);
my %bin =   map {$_ => [0, 0]} (0, 40, 183, 503, 442, 259, 244);

for my $i (0 .. $#class) {
    my $hkey = $class[$i];

    @{$bin{$hkey}} = ($bin{$hkey}[0]+1, $bin{$hkey}[1]+ $qty[$i]);
}

Dump (\%bin);