buffer equilibrium problem

Molar mass of CH3COOH = 12x2 + 1x4 + 16x2 = 60 g/mol
Molar mass of CH3COONa = 12x2 + 1x3 + 16x2 + 23 = 82 g/mol

Initial concentration [CH3COOH]o = 4.0/60 = 0.0667 M
Initial concentration [CH3COO^-]o = 6.0/82 = 0.0732 M

CH3COOH ≒ CH3COO-(aq) + H+(aq)

At equilibrium:
pH = pKa - log([CH3COOH]/[CH3COO^-])
pH = pKa - log([CH3COOH]o/[CH3COO^-]o)
pH = -log(1.8 x 10^-5) - log(0.0667/0.0732)
pH = 4.8 (2 sig. figs.)
pH= (or 4.79 (3 sig. figs.))