(a) Each unit owner shall be entitled to an undivided interest in the common areas and facilities in the ratio expressed in the declaration. Such ratio shall be in the approximate relation that the fair market value of the unit at the date of the declaration bears to the then aggregate fair market value of all the units having an interest in said common areas and facilities.
(b) The ratio of the undivided interest of each unit owner in the common areas and facilities as expressed in the declaration shall have a permanent character and shall not be altered except with the unanimous consent of all unit owners expressed in an amended declaration duly recorded.
(c) The undivided interest in the common areas and facilities shall not be separated from the unit to which it appertains and shall be deemed conveyed or encumbered with the unit even though such interest is not expressly mentioned or described in the conveyance or other instrument.