A bakelite beaker has volume capacity of 500 cc at 30°C. When it is partially filled with Vm volume (at 30°C) of mercury, it is found that the unfilled volume of the beaker remains constant as temperature is varied. If γ(beaker) = 6 × 10^–6°C–1 and γ(mercury) = 1.5 10^-4 °C-1 , where γ is the coefficient of volume expansion, then Vm (in cc) is close to ___________.