  A detailed analysis of two different theoretical equations of state for a
binary mixture of additive hard disks [C. Barrio and J. R. Solana, Phys. Rev. E
63, 011201 (2001); A. Santos, S. B. Yuste and M. Lopez de Haro, Mol. Phys. 96,
1 (1999)], including their comparison with Monte Carlo results, is carried out.
It is found that both proposals, which require the equation of state of the
single component system as input, lead to comparable accuracy when the same
input is used in both, but the one advocated by Santos et al. is simpler and
complies with the exact limit in which the small disks are point particles.
