my @names_marks = ("cliff 76", "john 52", "keith 90", "rob 52");

my (%hash, @names, @marks);

foreach (@names_marks) {
  my ($name, $mark) = split / /, $_;
  $hash{$_} = [ucfirst($name), $mark];
}
## then sort by the $mark
foreach my $key (sort {$b->[1] <=> $a->[1]} keys %hash) {
  print "\$key: $key \$value: $hash{$key}->[0] $hash{$key}->[1]\n";
}