A Bakelite beaker has volume capacity of 500 cc at 30ºC. When it is partially filled with  Vm volume (at 30ºC) of mercury, it is found that the unfilled volume of the beaker remains constant as temperature is varies. If γbeaker=6×10−6ºC−1 and  γmercury=1.5×10−4ºC−1, where γ is the coefficient of volume expansion, then Vm  (in cc) is close to ________.