  It has been recently pointed out by Farr and Groot (arXiv:0912.0852) and by
Kyrylyuk and Philipse (Prog. Colloid Polym. Sci., 2010, in press) that our
theoretical result for the jamming density of a binary mixture of hard spheres
(arXiv:0903.5099) apparently violates an upper bound that is obtained by
considering the limit where the diameter ratio r = DA/DB goes to infinity. We
believe that this apparent contradiction is the consequence of a
misunderstanding, which we try to clarify here.
