use strict;
use List::MoreUtils qw/mesh natatime/;
use Data::Dumper;

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

my $it = natatime 2, mesh @class, @qty;
while ( my ( $class, $quantity ) = $it->() ) {
    ( $bin{$class}->[0] )++;
    $bin{$class}->[1] += $quantity;
}

print Dumper( \%bin );